Add initial configuration, tokens, and widgets for M3E components

- Introduced `.gitignore` and `.metadata` for apps and examples.
- Added Flutter/Dart analysis configurations (`analysis_options.yaml`).
- Implemented foundational tokens and themes for M3E (colors, shapes).
- Created base implementations for `IconButtonM3E` and `SplitButtonM3E`.
- Set up CI workflow (`ci.yaml`) to automate testing and analysis.

.github/workflows/ci.yaml

@@ -0,0 +1,23 @@
+name: CI
+on:
+  push:
+  pull_request:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: subosito/flutter-action@v2
+        with:
+          channel: stable
+      - name: Install Melos
+        run: dart pub global activate melos
+      - name: Bootstrap
+        run: melos bootstrap
+      - name: Format
+        run: melos run format
+      - name: Analyze
+        run: melos run analyze
+      - name: Test
+        run: melos run test

.gitignore

@@ -7,6 +7,24 @@
 .buildlog/
 .history
 
+# Other
+.dart_tool/
+.packages
+.melos_tool
+build/
+ios/
+android/
+macos/
+windows/
+linux/
+web/
+.idea/
+.vscode/
+.flutter-plugins
+.flutter-plugins-dependencies
+pubspec.lock
+coverage/
+
 
 
 # Flutter repo-specific

README.md

@@ -0,0 +1,24 @@
+# Material 3 Expressive – Flutter Monorepo (Starter)
+
+This is a starter monorepo for **Material 3 Expressive (M3E)** Flutter packages.
+
+- `packages/m3e_design` – design language core (tokens, ThemeExtension, motion)
+- `packages/m3e_collection` – re-exports all component packages
+- `packages/icon_button_m3e` – example component (uses `m3e_design`)
+- `packages/split_button_m3e` – example split button component
+- `apps/gallery` – showcase app that consumes `m3e_collection`
+
+## Quick start
+
+```bash
+dart pub global activate melos
+melos bootstrap
+
+# run the gallery
+cd apps/gallery
+flutter run
+```
+
+## Structure
+
+See `melos.yaml`, `analysis_options.yaml`, and the package-level READMEs.

analysis_options.yaml

@@ -0,0 +1,11 @@
+linter:
+  rules:
+    always_declare_return_types: true
+    directives_ordering: true
+    prefer_single_quotes: true
+    sort_pub_dependencies: true
+
+analyzer:
+  exclude:
+    - "**/*.g.dart"
+    - "**/*.freezed.dart"

apps/gallery/.gitignore

@@ -0,0 +1,45 @@
+# Miscellaneous
+*.class
+*.log
+*.pyc
+*.swp
+.DS_Store
+.atom/
+.build/
+.buildlog/
+.history
+.svn/
+.swiftpm/
+migrate_working_dir/
+
+# IntelliJ related
+*.iml
+*.ipr
+*.iws
+.idea/
+
+# The .vscode folder contains launch configuration and tasks you configure in
+# VS Code which you may wish to be included in version control, so this line
+# is commented out by default.
+#.vscode/
+
+# Flutter/Dart/Pub related
+**/doc/api/
+**/ios/Flutter/.last_build_id
+.dart_tool/
+.flutter-plugins-dependencies
+.pub-cache/
+.pub/
+/build/
+/coverage/
+
+# Symbolication related
+app.*.symbols
+
+# Obfuscation related
+app.*.map.json
+
+# Android Studio will place build artifacts here
+/android/app/debug
+/android/app/profile
+/android/app/release

apps/gallery/.metadata

@@ -0,0 +1,45 @@
+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled and should not be manually edited.
+
+version:
+  revision: "d693b4b9dbac2acd4477aea4555ca6dcbea44ba2"
+  channel: "stable"
+
+project_type: app
+
+# Tracks metadata for the flutter migrate command
+migration:
+  platforms:
+    - platform: root
+      create_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+      base_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+    - platform: android
+      create_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+      base_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+    - platform: ios
+      create_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+      base_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+    - platform: linux
+      create_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+      base_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+    - platform: macos
+      create_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+      base_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+    - platform: web
+      create_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+      base_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+    - platform: windows
+      create_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+      base_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+
+  # User provided section
+
+  # List of Local paths (relative to this file) that should be
+  # ignored by the migrate tool.
+  #
+  # Files that are not part of the templates will be ignored by default.
+  unmanaged_files:
+    - 'lib/main.dart'
+    - 'ios/Runner.xcodeproj/project.pbxproj'

apps/gallery/README.md

@@ -0,0 +1,16 @@
+# m3e_gallery
+
+A new Flutter project.
+
+## Getting Started
+
+This project is a starting point for a Flutter application.
+
+A few resources to get you started if this is your first Flutter project:
+
+- [Lab: Write your first Flutter app](https://docs.flutter.dev/get-started/codelab)
+- [Cookbook: Useful Flutter samples](https://docs.flutter.dev/cookbook)
+
+For help getting started with Flutter development, view the
+[online documentation](https://docs.flutter.dev/), which offers tutorials,
+samples, guidance on mobile development, and a full API reference.

apps/gallery/analysis_options.yaml

@@ -0,0 +1,28 @@
+# This file configures the analyzer, which statically analyzes Dart code to
+# check for errors, warnings, and lints.
+#
+# The issues identified by the analyzer are surfaced in the UI of Dart-enabled
+# IDEs (https://dart.dev/tools#ides-and-editors). The analyzer can also be
+# invoked from the command line by running `flutter analyze`.
+
+# The following line activates a set of recommended lints for Flutter apps,
+# packages, and plugins designed to encourage good coding practices.
+# include: package:flutter_lints/flutter.yaml
+
+linter:
+  # The lint rules applied to this project can be customized in the
+  # section below to disable rules from the `package:flutter_lints/flutter.yaml`
+  # included above or to enable additional rules. A list of all available lints
+  # and their documentation is published at https://dart.dev/lints.
+  #
+  # Instead of disabling a lint rule for the entire project in the
+  # section below, it can also be suppressed for a single line of code
+  # or a specific dart file by using the `// ignore: name_of_lint` and
+  # `// ignore_for_file: name_of_lint` syntax on the line or in the file
+  # producing the lint.
+  rules:
+    # avoid_print: false  # Uncomment to disable the `avoid_print` rule
+    prefer_single_quotes: true  # Uncomment to enable the `prefer_single_quotes` rule
+
+# Additional information about this file can be found at
+# https://dart.dev/guides/language/analysis-options

apps/gallery/lib/main.dart

@@ -0,0 +1,560 @@
+import 'package:flutter/material.dart';
+import 'package:m3e_collection/m3e_collection.dart';
+
+void main() => runApp(const GalleryApp());
+
+class GalleryApp extends StatelessWidget {
+  const GalleryApp({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    final base = ThemeData(useMaterial3: true, colorSchemeSeed: Colors.purple);
+    return MaterialApp(
+      title: 'M3E Gallery',
+      theme: withM3ETheme(base),
+      home: const GalleryHome(),
+      debugShowCheckedModeBanner: false,
+    );
+  }
+}
+
+class GalleryHome extends StatefulWidget {
+  const GalleryHome({super.key});
+
+  @override
+  State<GalleryHome> createState() => _GalleryHomeState();
+}
+
+class _GalleryHomeState extends State<GalleryHome> {
+  // Navigation examples
+  int _navBarIndex = 0;
+  int _railIndex = 0;
+
+  // Slider examples
+  double _sliderValue = 0.4;
+  RangeValues _rangeValues = const RangeValues(0.25, 0.75);
+
+  // Progress examples
+  double _progressValue = 0.6;
+
+  void onPressed() {
+    // Placeholder function for button onPressed
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final cs = Theme.of(context).colorScheme;
+    final m3e =
+        Theme.of(context).extension<M3ETheme>() ?? M3ETheme.defaults(cs);
+    return Scaffold(
+      appBar: AppBarM3E(
+        titleText: 'M3E Gallery',
+        actions: const [
+          Icon(Icons.search),
+          SizedBox(width: 8),
+          Icon(Icons.more_vert),
+        ],
+      ),
+      body: ListView(
+        padding: const EdgeInsets.all(16),
+        children: [
+          // Icon buttons
+          Text('IconButtonM3E', style: Theme.of(context).textTheme.titleLarge),
+          const SizedBox(height: 12),
+          Wrap(
+            spacing: 12,
+            runSpacing: 12,
+            children: [
+              IconButtonM3E(
+                  icon: Icon(Icons.favorite),
+                  variant: IconButtonM3EVariant.filled,
+                  onPressed: onPressed),
+              IconButtonM3E(
+                  icon: Icon(Icons.favorite),
+                  variant: IconButtonM3EVariant.tonal,
+                  onPressed: onPressed),
+              IconButtonM3E(
+                  icon: Icon(Icons.favorite),
+                  variant: IconButtonM3EVariant.outlined,
+                  onPressed: onPressed),
+              IconButtonM3E(
+                  icon: Icon(Icons.favorite),
+                  variant: IconButtonM3EVariant.standard,
+                  onPressed: onPressed),
+            ],
+          ),
+
+          const SizedBox(height: 24),
+          // Split Button
+          Text('SplitButtonM3E', style: Theme.of(context).textTheme.titleLarge),
+          const SizedBox(height: 12),
+          Wrap(
+            spacing: 12,
+            runSpacing: 12,
+            children: [
+              SplitButtonM3E<String>(
+                label: 'Primary',
+                onPressed: () {},
+                items: const [
+                  SplitButtonM3EItem<String>(value: 'one', child: 'One'),
+                  SplitButtonM3EItem<String>(value: 'two', child: 'Two'),
+                ],
+              ),
+              SplitButtonM3E<String>(
+                label: 'Tonal',
+                emphasis: SplitButtonM3EEmphasis.tonal,
+                onPressed: () {},
+                items: const [
+                  SplitButtonM3EItem<String>(value: 'one', child: 'One'),
+                  SplitButtonM3EItem<String>(value: 'two', child: 'Two'),
+                ],
+              ),
+              SplitButtonM3E<String>(
+                label: 'Outlined',
+                emphasis: SplitButtonM3EEmphasis.outlined,
+                onPressed: () {},
+                items: const [
+                  SplitButtonM3EItem<String>(value: 'one', child: 'One'),
+                  SplitButtonM3EItem<String>(value: 'two', child: 'Two'),
+                ],
+              ),
+              SplitButtonM3E<String>(
+                label: 'Text',
+                emphasis: SplitButtonM3EEmphasis.text,
+                onPressed: () {},
+                items: const [
+                  SplitButtonM3EItem<String>(value: 'one', child: 'One'),
+                  SplitButtonM3EItem<String>(value: 'two', child: 'Two'),
+                ],
+              ),
+            ],
+          ),
+
+          const SizedBox(height: 24),
+          // Buttons
+          Text('ButtonM3E', style: Theme.of(context).textTheme.titleLarge),
+          const SizedBox(height: 12),
+          Wrap(spacing: 12, runSpacing: 12, children: [
+            Wrap(
+              spacing: 12,
+              runSpacing: 12,
+              children: [
+                ButtonM3E(
+                    labelText: 'Filled',
+                    variant: ButtonM3EVariant.filled,
+                    onPressed: onPressed),
+                ButtonM3E(
+                    labelText: 'Tonal',
+                    variant: ButtonM3EVariant.tonal,
+                    onPressed: onPressed),
+                ButtonM3E(
+                    labelText: 'Outlined',
+                    variant: ButtonM3EVariant.outlined,
+                    onPressed: onPressed),
+                ButtonM3E(
+                    labelText: 'Text',
+                    variant: ButtonM3EVariant.text,
+                    onPressed: onPressed),
+                ButtonM3E(
+                    labelText: 'Elevated',
+                    variant: ButtonM3EVariant.elevated,
+                    onPressed: onPressed),
+              ],
+            ),
+            Wrap(
+              spacing: 12,
+              runSpacing: 12,
+              children: [
+                ButtonM3E(
+                    labelText: 'Filled',
+                    variant: ButtonM3EVariant.filled,
+                    shapeFamily: ButtonM3EShapeFamily.square,
+                    onPressed: onPressed),
+                ButtonM3E(
+                    labelText: 'Tonal',
+                    variant: ButtonM3EVariant.tonal,
+                    shapeFamily: ButtonM3EShapeFamily.square,
+                    onPressed: onPressed),
+                ButtonM3E(
+                    labelText: 'Outlined',
+                    variant: ButtonM3EVariant.outlined,
+                    shapeFamily: ButtonM3EShapeFamily.square,
+                    onPressed: onPressed),
+                ButtonM3E(
+                    labelText: 'Text',
+                    variant: ButtonM3EVariant.text,
+                    shapeFamily: ButtonM3EShapeFamily.square,
+                    onPressed: onPressed),
+                ButtonM3E(
+                    labelText: 'Elevated',
+                    variant: ButtonM3EVariant.elevated,
+                    shapeFamily: ButtonM3EShapeFamily.square,
+                    onPressed: onPressed),
+              ],
+            ),
+          ]),
+
+          const SizedBox(height: 24),
+          // Button groups
+          Text('ButtonGroupM3E', style: Theme.of(context).textTheme.titleLarge),
+          const SizedBox(height: 12),
+          // Standard group, round, md
+          ButtonGroupM3E(
+            type: ButtonGroupM3EType.standard,
+            shape: ButtonGroupM3EShape.round,
+            size: ButtonGroupM3ESize.md,
+            children: const [
+              IconButtonM3E(icon: Icon(Icons.skip_previous)),
+              IconButtonM3E(icon: Icon(Icons.play_arrow)),
+              IconButtonM3E(icon: Icon(Icons.skip_next)),
+            ],
+          ),
+          const SizedBox(height: 12),
+          // Connected group with divider and clipping for outer corners
+          ButtonGroupM3E(
+            type: ButtonGroupM3EType.connected,
+            shape: ButtonGroupM3EShape.round,
+            size: ButtonGroupM3ESize.lg,
+            showDividers: true,
+            clipBehavior: Clip.hardEdge,
+            equalizeWidths: true,
+            semanticLabel: 'Actions',
+            children: [
+              SplitButtonM3E<String>(
+                label: 'Primary',
+                onPressed: () {},
+                items: const [
+                  SplitButtonM3EItem<String>(value: 'one', child: 'One'),
+                  SplitButtonM3EItem<String>(value: 'two', child: 'Two'),
+                ],
+              ),
+              SplitButtonM3E<String>(
+                label: 'Tonal',
+                emphasis: SplitButtonM3EEmphasis.tonal,
+                onPressed: () {},
+                items: const [
+                  SplitButtonM3EItem<String>(value: 'one', child: 'One'),
+                  SplitButtonM3EItem<String>(value: 'two', child: 'Two'),
+                ],
+              ),
+            ],
+          ),
+          const SizedBox(height: 12),
+          // Square, compact, vertical wrap
+          ButtonGroupM3E(
+            type: ButtonGroupM3EType.standard,
+            shape: ButtonGroupM3EShape.square,
+            size: ButtonGroupM3ESize.sm,
+            density: ButtonGroupM3EDensity.compact,
+            direction: Axis.vertical,
+            children: const [
+              IconButtonM3E(icon: Icon(Icons.view_agenda_outlined)),
+              IconButtonM3E(icon: Icon(Icons.table_rows_outlined)),
+              IconButtonM3E(icon: Icon(Icons.grid_view_outlined)),
+            ],
+          ),
+
+          const SizedBox(height: 24),
+          // Toolbar
+          Text('ToolbarM3E', style: Theme.of(context).textTheme.titleLarge),
+          const SizedBox(height: 12),
+          ToolbarM3E(
+            titleText: 'Toolbar Title',
+            subtitleText: 'Subtitle',
+            actions: [
+              ToolbarActionM3E(icon: Icons.search, onPressed: () {}),
+              ToolbarActionM3E(icon: Icons.share, onPressed: () {}),
+              ToolbarActionM3E(
+                  icon: Icons.delete,
+                  onPressed: () {},
+                  isDestructive: true,
+                  label: 'Delete'),
+              ToolbarActionM3E(
+                  icon: Icons.settings, onPressed: () {}, label: 'Settings'),
+            ],
+            maxInlineActions: 2,
+          ),
+
+          const SizedBox(height: 24),
+          // FABs
+          Text('FabM3E', style: Theme.of(context).textTheme.titleLarge),
+          const SizedBox(height: 12),
+          Wrap(
+            spacing: 12,
+            runSpacing: 12,
+            children: const [
+              FabM3E(icon: Icon(Icons.add)),
+              FabM3E(icon: Icon(Icons.edit), kind: FabM3EKind.secondary),
+              FabM3E(icon: Icon(Icons.share), kind: FabM3EKind.tertiary),
+              FabM3E(icon: Icon(Icons.more_horiz), kind: FabM3EKind.surface),
+              FabM3E(icon: Icon(Icons.add), size: FabM3ESize.small),
+              FabM3E(icon: Icon(Icons.add), size: FabM3ESize.large),
+            ],
+          ),
+          const SizedBox(height: 12),
+          Wrap(
+            spacing: 12,
+            runSpacing: 12,
+            children: const [
+              ExtendedFabM3E(label: Text('Create'), icon: Icon(Icons.add)),
+              ExtendedFabM3E(
+                  label: Text('Edit'),
+                  icon: Icon(Icons.edit),
+                  kind: FabM3EKind.secondary),
+              ExtendedFabM3E(
+                  label: Text('Share'),
+                  icon: Icon(Icons.share),
+                  kind: FabM3EKind.tertiary),
+            ],
+          ),
+          const SizedBox(height: 12),
+          SizedBox(
+            height: 180,
+            child: Stack(
+              children: [
+                Positioned.fill(
+                  child: Container(
+                    decoration: BoxDecoration(
+                      color:
+                          Theme.of(context).colorScheme.surfaceContainerHighest,
+                      borderRadius: m3e.shapes.round.lg,
+                    ),
+                  ),
+                ),
+                Align(
+                  alignment: Alignment.bottomRight,
+                  child: FabMenuM3E(
+                    primaryFab: const FabM3E(icon: Icon(Icons.menu)),
+                    items: [
+                      FabMenuItem(
+                          icon: const Icon(Icons.image),
+                          label: const Text('Image'),
+                          onPressed: () {}),
+                      FabMenuItem(
+                          icon: const Icon(Icons.camera_alt),
+                          label: const Text('Camera'),
+                          onPressed: () {}),
+                      FabMenuItem(
+                          icon: const Icon(Icons.file_upload),
+                          label: const Text('Upload'),
+                          onPressed: () {}),
+                    ],
+                  ),
+                ),
+              ],
+            ),
+          ),
+
+          const SizedBox(height: 24),
+          // Loading indicators
+          Text('LoadingIndicatorM3E',
+              style: Theme.of(context).textTheme.titleLarge),
+          const SizedBox(height: 12),
+          Wrap(
+            spacing: 16,
+            runSpacing: 16,
+            crossAxisAlignment: WrapCrossAlignment.center,
+            children: const [
+              LoadingIndicatorM3E(
+                  variant: LoadingIndicatorM3EVariant.defaultStyle),
+              LoadingIndicatorM3E(
+                  variant: LoadingIndicatorM3EVariant.contained),
+            ],
+          ),
+
+          const SizedBox(height: 24),
+          // Progress indicators
+          Text('ProgressIndicatorM3E',
+              style: Theme.of(context).textTheme.titleLarge),
+          const SizedBox(height: 12),
+          Wrap(
+            spacing: 16,
+            runSpacing: 16,
+            crossAxisAlignment: WrapCrossAlignment.center,
+            children: [
+              const CircularProgressM3E(),
+              const CircularProgressM3E(size: ProgressM3ESize.small),
+              CircularProgressM3E(
+                  size: ProgressM3ESize.large,
+                  value: _progressValue,
+                  showCenterLabel: true),
+              const LinearProgressM3E(minWidth: 200),
+              LinearProgressM3E(minWidth: 200, value: _progressValue),
+              const LinearProgressM3E(
+                  minWidth: 200,
+                  variant: LinearProgressM3EVariant.indeterminate),
+              const LinearProgressM3E(
+                  minWidth: 200, variant: LinearProgressM3EVariant.query),
+              const LinearProgressM3E(
+                  minWidth: 200,
+                  variant: LinearProgressM3EVariant.buffer,
+                  bufferValue: 0.8,
+                  value: 0.4),
+            ],
+          ),
+
+          const SizedBox(height: 24),
+          // Sliders
+          Text('SliderM3E', style: Theme.of(context).textTheme.titleLarge),
+          const SizedBox(height: 12),
+          SliderM3E(
+            value: _sliderValue,
+            onChanged: (v) => setState(() => _sliderValue = v),
+            min: 0,
+            max: 100,
+            label: '${_sliderValue.toStringAsFixed(0)}',
+            startIcon: const Icon(Icons.volume_mute),
+            endIcon: const Icon(Icons.volume_up),
+          ),
+          const SizedBox(height: 8),
+          RangeSliderM3E(
+            values: _rangeValues,
+            onChanged: (v) => setState(() => _rangeValues = v),
+            min: 0,
+            max: 100,
+            labels: RangeLabels(
+              _rangeValues.start.toStringAsFixed(0),
+              _rangeValues.end.toStringAsFixed(0),
+            ),
+          ),
+
+          const SizedBox(height: 24),
+          // Navigation Bar
+          Text('NavigationBarM3E',
+              style: Theme.of(context).textTheme.titleLarge),
+          const SizedBox(height: 12),
+          NavigationBarM3E(
+            selectedIndex: _navBarIndex,
+            onDestinationSelected: (i) => setState(() => _navBarIndex = i),
+            indicatorStyle: NavBarM3EIndicatorStyle.pill,
+            destinations: const [
+              NavigationDestinationM3E(
+                  icon: Icon(Icons.home_outlined),
+                  selectedIcon: Icon(Icons.home),
+                  label: 'Home'),
+              NavigationDestinationM3E(
+                  icon: Icon(Icons.search_outlined),
+                  selectedIcon: Icon(Icons.search),
+                  label: 'Search',
+                  badgeDot: true),
+              NavigationDestinationM3E(
+                  icon: Icon(Icons.favorite_outline),
+                  selectedIcon: Icon(Icons.favorite),
+                  label: 'Favorites',
+                  badgeCount: 3),
+              NavigationDestinationM3E(
+                  icon: Icon(Icons.person_outline),
+                  selectedIcon: Icon(Icons.person),
+                  label: 'Profile'),
+            ],
+          ),
+
+          const SizedBox(height: 24),
+          // Navigation Rail
+          Text('NavigationRailM3E',
+              style: Theme.of(context).textTheme.titleLarge),
+          const SizedBox(height: 12),
+          Container(
+            decoration: BoxDecoration(
+              color: Theme.of(context).colorScheme.surfaceContainerHighest,
+              borderRadius: m3e.shapes.round.lg,
+            ),
+            height: 180,
+            child: Row(
+              children: [
+                NavigationRailM3E(
+                  selectedIndex: _railIndex,
+                  onDestinationSelected: (i) => setState(() => _railIndex = i),
+                  indicatorStyle: RailIndicatorStyle.pill,
+                  destinations: const [
+                    RailDestinationM3E(
+                        icon: Icon(Icons.dashboard_outlined),
+                        selectedIcon: Icon(Icons.dashboard),
+                        label: 'Dashboard'),
+                    RailDestinationM3E(
+                        icon: Icon(Icons.analytics_outlined),
+                        selectedIcon: Icon(Icons.analytics),
+                        label: 'Reports'),
+                    RailDestinationM3E(
+                        icon: Icon(Icons.settings_outlined),
+                        selectedIcon: Icon(Icons.settings),
+                        label: 'Settings'),
+                  ],
+                ),
+                const VerticalDivider(width: 1),
+                Expanded(
+                  child: Center(
+                    child: Text('Selected: $_railIndex'),
+                  ),
+                ),
+              ],
+            ),
+          ),
+
+          const SizedBox(height: 24),
+          // Sliver App Bar demo route
+          Text('App bars', style: Theme.of(context).textTheme.titleLarge),
+          const SizedBox(height: 12),
+          Wrap(
+            spacing: 12,
+            children: [
+              const ButtonM3E(labelText: 'Open SliverAppBarM3E Demo'),
+              // Use GestureDetector to navigate when tapping the button label area
+            ]
+                .map((w) => GestureDetector(
+                      onTap: () => Navigator.of(context).push(
+                        MaterialPageRoute(
+                            builder: (_) => const _SliverAppBarDemoPage()),
+                      ),
+                      child: w,
+                    ))
+                .toList(),
+          ),
+
+          const SizedBox(height: 48),
+          // Theming surface example remains
+          Container(
+            padding: const EdgeInsets.all(16),
+            decoration: BoxDecoration(
+              color: m3e.colors.surfaceStrong,
+              borderRadius: m3e.shapes.square.lg,
+            ),
+            child: Text('Surface strong example',
+                style: Theme.of(context)
+                    .textTheme
+                    .titleMedium
+                    ?.copyWith(color: cs.onSurface)),
+          ),
+        ],
+      ),
+    );
+  }
+}
+
+class _SliverAppBarDemoPage extends StatelessWidget {
+  const _SliverAppBarDemoPage();
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: CustomScrollView(
+        slivers: [
+          const SliverAppBarM3E(
+            titleText: 'SliverAppBarM3E',
+            pinned: true,
+            floating: false,
+            variant: AppBarM3EVariant.large,
+          ),
+          SliverList(
+            delegate: SliverChildBuilderDelegate(
+              (context, index) => ListTile(
+                title: Text('Item #$index'),
+              ),
+              childCount: 30,
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}

apps/gallery/pubspec.yaml

@@ -0,0 +1,16 @@
+name: m3e_gallery
+description: Gallery app for Material 3 Expressive packages.
+publish_to: none
+
+environment:
+  sdk: ">=3.5.0 <4.0.0"
+
+dependencies:
+  flutter:
+    sdk: flutter
+  m3e_collection:
+    path: ../../packages/m3e_collection
+  material_color_utilities: ^0.11.0
+
+flutter:
+  uses-material-design: true

apps/gallery/pubspec_overrides.yaml

@@ -0,0 +1,30 @@
+# melos_managed_dependency_overrides: icon_button_m3e,m3e_collection,m3e_design,split_button_m3e,app_bar_m3e,button_group_m3e,button_m3e,fab_m3e,loading_indicator_m3e,navigation_bar_m3e,navigation_rail_m3e,progress_indicator_m3e,slider_m3e,toolbar_m3e
+dependency_overrides:
+  app_bar_m3e:
+    path: ..\\..\\packages\\app_bar_m3e
+  button_group_m3e:
+    path: ..\\..\\packages\\button_group_m3e
+  button_m3e:
+    path: ..\\..\\packages\\button_m3e
+  fab_m3e:
+    path: ..\\..\\packages\\fab_m3e
+  icon_button_m3e:
+    path: ..\\..\\packages\\icon_button_m3e
+  loading_indicator_m3e:
+    path: ..\\..\\packages\\loading_indicator_m3e
+  m3e_collection:
+    path: ..\\..\\packages\\m3e_collection
+  m3e_design:
+    path: ..\\..\\packages\\m3e_design
+  navigation_bar_m3e:
+    path: ..\\..\\packages\\navigation_bar_m3e
+  navigation_rail_m3e:
+    path: ..\\..\\packages\\navigation_rail_m3e
+  progress_indicator_m3e:
+    path: ..\\..\\packages\\progress_indicator_m3e
+  slider_m3e:
+    path: ..\\..\\packages\\slider_m3e
+  split_button_m3e:
+    path: ..\\..\\packages\\split_button_m3e
+  toolbar_m3e:
+    path: ..\\..\\packages\\toolbar_m3e

melos.yaml

@@ -0,0 +1,19 @@
+name: m3e
+packages:
+  - "packages/*"
+  - "apps/*"
+
+command:
+  bootstrap:
+    usePubspecOverrides: true
+
+scripts:
+  bootstrap: melos bootstrap
+  clean: melos exec -- flutter clean
+  get: melos exec -- flutter pub get
+  format: melos exec -- dart format --set-exit-if-changed .
+  analyze: melos exec -- dart analyze --fatal-infos --fatal-warnings
+  test: melos exec -- flutter test --coverage
+  create:
+    run: dart run tool/create_component.dart
+    description: Scaffold a new [component]_m3e package (melos run create -- name=badge)

melos_m3e.iml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="WEB_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
+      <excludeFolder url="file://$MODULE_DIR$/packages/split_button_m3e/example/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/packages/split_button_m3e/example/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/packages/split_button_m3e/example/build" />
+    </content>
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="Dart SDK" level="project" />
+    <orderEntry type="library" name="Dart Packages" level="project" />
+  </component>
+</module>

packages/app_bar_m3e/README.md

@@ -0,0 +1,90 @@
+# app_bar_m3e
+
+Expressive **App Bar** for Flutter (Material 3 Expressive).  
+Small (standard) bar for `Scaffold.appBar`, plus **Medium** & **Large** collapsing variants via a sliver.
+
+> Uses `m3e_design` tokens for color, typography, spacing, and shapes.
+
+## Monorepo Setup
+
+Place alongside `m3e_design` in your repo:
+
+```
+packages/
+  m3e_design/
+  app_bar_m3e/
+```
+
+`pubspec.yaml` references `../m3e_design` by default.
+
+## API
+
+### Small App Bar
+
+```dart
+AppBarM3E(
+  leading: IconButton(icon: const BackButtonIcon(), onPressed: () {}),
+  titleText: 'Inbox',
+  actions: [IconButton(icon: const Icon(Icons.search), onPressed: () {})],
+  centerTitle: false,
+  shapeFamily: AppBarM3EShapeFamily.round,
+  density: AppBarM3EDensity.regular,
+);
+```
+
+Use in a `Scaffold`:
+
+```dart
+Scaffold(
+  appBar: const AppBarM3E(titleText: 'Inbox'),
+  body: ...
+);
+```
+
+### Sliver App Bar (Medium / Large)
+
+```dart
+CustomScrollView(
+  slivers: [
+    SliverAppBarM3E(
+      variant: AppBarM3EVariant.large,
+      titleText: 'Gallery',
+      pinned: true,
+    ),
+    // ... content slivers
+  ],
+);
+```
+
+- `variant: medium` uses expanded height ≈112dp (collapses to ~64dp).
+- `variant: large` uses expanded height ≈152dp (collapses to ~64dp).
+- Colors, shapes, and typography come from `m3e_design`'s `M3ETheme` extension.
+
+## Theme Integration
+
+`app_bar_m3e` reads the `M3ETheme` extension from your `ThemeData`:
+
+```dart
+final m3e = Theme.of(context).extension<M3ETheme>() ??
+            M3ETheme.defaults(Theme.of(context).colorScheme);
+```
+
+It uses:
+- `m3e.colors.surfaceContainerHigh` for background
+- `m3e.type.titleLarge` for collapsed titles
+- `m3e.type.headlineSmallEmphasized` for expanded titles
+- `m3e.shapes.round|square` for container shape
+- `m3e.spacing.md` for horizontal padding
+
+Override by supplying `backgroundColor`, `foregroundColor`, `toolbarHeight`, etc.
+
+## Notes
+
+- For collapsing behavior, use the sliver variant inside a `CustomScrollView`.
+- `AppBarM3E` (small) is a `PreferredSizeWidget` suitable for `Scaffold.appBar`.
+- Medium/Large variants rely on `FlexibleSpaceBar` for expanded titles.
+- When `density: compact`, default heights reduce by ~8dp.
+
+## License
+
+MIT

packages/app_bar_m3e/lib/app_bar_m3e.dart

@@ -0,0 +1,5 @@
+library app_bar_m3e;
+
+export 'src/app_bar_m3e_enums.dart';
+export 'src/app_bar_m3e_widget.dart';
+export 'src/sliver_app_bar_m3e.dart';

packages/app_bar_m3e/lib/src/_tokens_adapter.dart

@@ -0,0 +1,74 @@
+import 'package:flutter/material.dart';
+import 'package:m3e_design/m3e_design.dart';
+import 'app_bar_m3e_enums.dart';
+
+@immutable
+class _AppBarMetrics {
+  final double smallHeight;
+  final double collapsedHeight;
+  final double mediumExpanded;
+  final double largeExpanded;
+  final EdgeInsetsGeometry horizontalPadding;
+  final double iconSize;
+  final double elevation;
+  const _AppBarMetrics({
+    required this.smallHeight,
+    required this.collapsedHeight,
+    required this.mediumExpanded,
+    required this.largeExpanded,
+    required this.horizontalPadding,
+    required this.iconSize,
+    required this.elevation,
+  });
+}
+
+_AppBarMetrics metricsFor(BuildContext context, AppBarM3EDensity density) {
+  final theme = Theme.of(context);
+  final m3e = theme.extension<M3ETheme>() ?? M3ETheme.defaults(theme.colorScheme);
+  final sp = m3e.spacing;
+
+  // Heights (approx per M3 specs; can be tuned via Theme extension in m3e_design if desired)
+  double small = 64;
+  double collapsed = 64;
+  double medium = 112;
+  double large = 152;
+
+  // Density tweaks
+  if (density == AppBarM3EDensity.compact) {
+    small -= 8;
+    collapsed -= 8;
+    medium -= 8;
+    large -= 8;
+  }
+
+  return _AppBarMetrics(
+    smallHeight: small,
+    collapsedHeight: collapsed,
+    mediumExpanded: medium,
+    largeExpanded: large,
+    horizontalPadding: EdgeInsets.symmetric(horizontal: sp.md),
+    iconSize: 24,
+    elevation: 0.0,
+  );
+}
+
+Color backgroundFor(BuildContext context) {
+  final theme = Theme.of(context);
+  final m3e = theme.extension<M3ETheme>() ?? M3ETheme.defaults(theme.colorScheme);
+  // Prefer container surfaces for bars
+  return m3e.colors.surfaceContainerHigh;
+}
+
+TextStyle titleStyleFor(BuildContext context, {bool collapsed = true}) {
+  final theme = Theme.of(context);
+  final m3e = theme.extension<M3ETheme>() ?? M3ETheme.defaults(theme.colorScheme);
+  return collapsed ? m3e.type.titleLarge : m3e.type.headlineSmallEmphasized;
+}
+
+ShapeBorder shapeFor(BuildContext context, AppBarM3EShapeFamily family) {
+  final theme = Theme.of(context);
+  final m3e = theme.extension<M3ETheme>() ?? M3ETheme.defaults(theme.colorScheme);
+  final set = family == AppBarM3EShapeFamily.round ? m3e.shapes.round : m3e.shapes.square;
+  // Use medium size radius for the bar container by default
+  return RoundedRectangleBorder(borderRadius: set.md);
+}

packages/app_bar_m3e/lib/src/app_bar_m3e_enums.dart

@@ -0,0 +1,3 @@
+enum AppBarM3EVariant { small, medium, large }
+enum AppBarM3EShapeFamily { round, square }
+enum AppBarM3EDensity { regular, compact }

packages/app_bar_m3e/lib/src/app_bar_m3e_widget.dart

@@ -0,0 +1,134 @@
+import 'package:flutter/material.dart';
+
+import '_tokens_adapter.dart';
+import 'app_bar_m3e_enums.dart';
+
+class AppBarM3E extends StatelessWidget implements PreferredSizeWidget {
+  const AppBarM3E({
+    super.key,
+    this.leading,
+    this.title,
+    this.titleText,
+    this.actions,
+    this.centerTitle = false,
+    this.backgroundColor,
+    this.foregroundColor,
+    this.elevation,
+    this.shapeFamily = AppBarM3EShapeFamily.round,
+    this.density = AppBarM3EDensity.regular,
+    this.toolbarHeight,
+    this.automaticallyImplyLeading = true,
+    this.clipBehavior = Clip.none,
+    this.semanticLabel,
+  });
+
+  final Widget? leading;
+  final Widget? title;
+  final String? titleText;
+  final List<Widget>? actions;
+  final bool centerTitle;
+
+  final Color? backgroundColor;
+  final Color? foregroundColor;
+  final double? elevation;
+  final AppBarM3EShapeFamily shapeFamily;
+  final AppBarM3EDensity density;
+  final double? toolbarHeight;
+  final bool automaticallyImplyLeading;
+  final Clip clipBehavior;
+  final String? semanticLabel;
+
+  @override
+  Size get preferredSize {
+    // Provide a reasonable non-null size; actual height applied in build.
+    return Size.fromHeight(toolbarHeight ?? 64);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final metrics = metricsFor(context, density);
+    final bg = backgroundColor ?? backgroundFor(context);
+    final fg = foregroundColor ?? Theme.of(context).colorScheme.onSurface;
+    final shape = shapeFor(context, shapeFamily);
+    final height = toolbarHeight ?? metrics.smallHeight;
+    final tStyle = titleStyleFor(context, collapsed: true);
+
+    final resolvedLeading = leading ?? (automaticallyImplyLeading
+        ? _maybeBackButton(context, fg)
+        : null);
+
+    final resolvedTitle = title ??
+        (titleText != null
+            ? Text(titleText!, style: tStyle, overflow: TextOverflow.ellipsis)
+            : null);
+
+    final bar = Material(
+      color: bg,
+      elevation: elevation ?? metrics.elevation,
+      shape: shape,
+      clipBehavior: clipBehavior,
+      child: SafeArea(
+        bottom: false,
+        child: SizedBox(
+          height: height,
+          child: Padding(
+            padding: metrics.horizontalPadding,
+            child: IconTheme.merge(
+              data: IconThemeData(size: metrics.iconSize, color: fg),
+              child: DefaultTextStyle(
+                style: tStyle.copyWith(color: fg),
+                child: Row(
+                  crossAxisAlignment: CrossAxisAlignment.center,
+                  children: [
+                    if (resolvedLeading != null) resolvedLeading,
+                    if (resolvedLeading != null) const SizedBox(width: 8),
+                    if (resolvedTitle != null)
+                      Expanded(
+                        child: Align(
+                          alignment: centerTitle ? Alignment.center : Alignment.centerLeft,
+                          child: resolvedTitle,
+                        ),
+                      )
+                    else
+                      const Spacer(),
+                    if (actions != null) ...[
+                      const SizedBox(width: 8),
+                      ..._withSpacers(actions!),
+                    ],
+                  ],
+                ),
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+
+    if (semanticLabel == null) return bar;
+    return Semantics(
+      container: true,
+      label: semanticLabel,
+      child: bar,
+    );
+  }
+
+  List<Widget> _withSpacers(List<Widget> items) {
+    final out = <Widget>[];
+    for (var i = 0; i < items.length; i++) {
+      out.add(items[i]);
+      if (i < items.length - 1) out.add(const SizedBox(width: 4));
+    }
+    return out;
+  }
+
+  Widget? _maybeBackButton(BuildContext context, Color fg) {
+    final canPop = Navigator.maybeOf(context)?.canPop() ?? false;
+    if (!canPop) return null;
+    return IconButton(
+      icon: const BackButtonIcon(),
+      color: fg,
+      onPressed: () => Navigator.maybeOf(context)?.maybePop(),
+      tooltip: MaterialLocalizations.of(context).backButtonTooltip,
+    );
+  }
+}

packages/app_bar_m3e/lib/src/sliver_app_bar_m3e.dart

@@ -0,0 +1,145 @@
+import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart' show RenderObject, RenderProxySliver;
+import 'package:flutter/semantics.dart' show SemanticsConfiguration;
+
+import '_tokens_adapter.dart';
+import 'app_bar_m3e_enums.dart';
+
+class SliverAppBarM3E extends StatelessWidget {
+  const SliverAppBarM3E({
+    super.key,
+    this.leading,
+    this.title,
+    this.titleText,
+    this.actions,
+    this.centerTitle = false,
+    this.backgroundColor,
+    this.foregroundColor,
+    this.pinned = true,
+    this.floating = false,
+    this.snap = false,
+    this.shapeFamily = AppBarM3EShapeFamily.round,
+    this.density = AppBarM3EDensity.regular,
+    this.variant = AppBarM3EVariant.medium,
+    this.semanticLabel,
+  });
+
+  final Widget? leading;
+  final Widget? title;
+  final String? titleText;
+  final List<Widget>? actions;
+  final bool centerTitle;
+
+  final Color? backgroundColor;
+  final Color? foregroundColor;
+  final bool pinned;
+  final bool floating;
+  final bool snap;
+  final AppBarM3EShapeFamily shapeFamily;
+  final AppBarM3EDensity density;
+  final AppBarM3EVariant variant;
+  final String? semanticLabel;
+
+  @override
+  Widget build(BuildContext context) {
+    final metrics = metricsFor(context, density);
+    final bg = backgroundColor ?? backgroundFor(context);
+    final fg = foregroundColor ?? Theme.of(context).colorScheme.onSurface;
+    final shape = shapeFor(context, shapeFamily);
+
+    final collapsedStyle = titleStyleFor(context, collapsed: true);
+    final expandedStyle = titleStyleFor(context, collapsed: false);
+
+    final collapsed = metrics.collapsedHeight;
+    final expanded = switch (variant) {
+      AppBarM3EVariant.medium => metrics.mediumExpanded,
+      AppBarM3EVariant.large => metrics.largeExpanded,
+      AppBarM3EVariant.small => metrics.smallHeight,
+    };
+
+    final resolvedTitleWidget = title ??
+        (titleText != null
+            ? Text(titleText!,
+                style: collapsedStyle, overflow: TextOverflow.ellipsis)
+            : null);
+
+    final bar = SliverAppBar(
+      pinned: pinned,
+      floating: floating,
+      snap: snap && floating,
+      backgroundColor: bg,
+      foregroundColor: fg,
+      collapsedHeight: collapsed,
+      expandedHeight: expanded,
+      centerTitle: centerTitle,
+      leading: leading,
+      title: resolvedTitleWidget,
+      actions: actions,
+      shape: shape,
+      flexibleSpace: _buildFlexibleSpace(context, expandedStyle),
+    );
+
+    if (semanticLabel == null) return bar;
+    return SliverSemantic(
+      label: semanticLabel!,
+      child: bar,
+    );
+  }
+
+  Widget? _buildFlexibleSpace(BuildContext context, TextStyle expandedStyle) {
+    switch (variant) {
+      case AppBarM3EVariant.small:
+        return null;
+      case AppBarM3EVariant.medium:
+      case AppBarM3EVariant.large:
+        final t = title ??
+            (titleText != null ? Text(titleText!, style: expandedStyle) : null);
+        if (t == null) return null;
+        return FlexibleSpaceBar(
+          titlePadding:
+              const EdgeInsetsDirectional.only(start: 16, bottom: 16, end: 16),
+          title: DefaultTextStyle(
+            style: expandedStyle.copyWith(
+              color: Theme.of(context).colorScheme.onSurface,
+            ),
+            child: t,
+          ),
+          collapseMode: CollapseMode.pin,
+          expandedTitleScale:
+              1.0, // Typography already larger; avoid scale morph
+        );
+    }
+  }
+}
+
+/// A helper to wrap a sliver with semantics label.
+class SliverSemantic extends SingleChildRenderObjectWidget {
+  const SliverSemantic({super.key, required this.label, required Widget child})
+      : super(child: child);
+  final String label;
+  @override
+  RenderObject createRenderObject(BuildContext context) =>
+      _SliverSemanticRender(label);
+  @override
+  void updateRenderObject(
+      BuildContext context, covariant _SliverSemanticRender renderObject) {
+    renderObject.label = label;
+  }
+}
+
+class _SliverSemanticRender extends RenderProxySliver {
+  _SliverSemanticRender(this._label);
+  String _label;
+  set label(String v) {
+    if (v == _label) return;
+    _label = v;
+    markNeedsSemanticsUpdate();
+  }
+
+  @override
+  void describeSemanticsConfiguration(SemanticsConfiguration config) {
+    super.describeSemanticsConfiguration(config);
+    config.label = _label;
+    config.isSemanticBoundary = true;
+  }
+}

packages/app_bar_m3e/melos_app_bar_m3e.iml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/example/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/android/.gradle" />
+      <excludeFolder url="file://$MODULE_DIR$/example/android/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/Flutter" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/Pods" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/Flutter" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/Pods" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/.symlinks" />
+    </content>
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="Dart SDK" level="project" />
+    <orderEntry type="library" name="Flutter Plugins" level="project" />
+    <orderEntry type="library" name="Dart Packages" level="project" />
+  </component>
+</module>

packages/app_bar_m3e/pubspec.yaml

@@ -0,0 +1,18 @@
+name: app_bar_m3e
+description: Expressive App Bar (Material 3 Expressive) with small/medium/large variants and Sliver integration.
+version: 0.1.0
+publish_to: none
+
+environment:
+  sdk: ">=3.5.0 <4.0.0"
+  flutter: ">=3.22.0"
+
+dependencies:
+  flutter:
+    sdk: flutter
+  m3e_design:
+    path: ../m3e_design
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter

packages/app_bar_m3e/pubspec_overrides.yaml

@@ -0,0 +1,4 @@
+# melos_managed_dependency_overrides: m3e_design
+dependency_overrides:
+  m3e_design:
+    path: ..\\m3e_design

packages/app_bar_m3e/test/app_bar_m3e_test.dart

@@ -0,0 +1,7 @@
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  test('placeholder', () {
+    expect(2 + 2, 4);
+  });
+}

packages/button_group_m3e/README.md

@@ -0,0 +1,100 @@
+# button_group_m3e
+
+Wrapper-only **Button Group** for Material 3 Expressive (M3E).  
+Arranges arbitrary action buttons and applies **group-level presentation**: type (standard/connected), shape family (round/square), size (XS–XL), density, and layout (axis, wrap).
+
+> Buttons themselves remain independent (no selection logic). Use your own M3E buttons (`icon_button_m3e`, `split_button_m3e`, etc.).
+
+## Install (in monorepo)
+
+Place this folder alongside `m3e_design`:
+
+```
+packages/
+  m3e_design/
+  button_group_m3e/
+```
+
+`pubspec.yaml` already expects `m3e_design` at `../m3e_design`.
+
+## API
+
+```dart
+class ButtonGroupM3E extends StatelessWidget {
+  const ButtonGroupM3E({
+    required List<Widget> children,
+    ButtonGroupM3EType type = ButtonGroupM3EType.standard,
+    ButtonGroupM3EShape shape = ButtonGroupM3EShape.round,
+    ButtonGroupM3ESize size = ButtonGroupM3ESize.md,
+    ButtonGroupM3EDensity density = ButtonGroupM3EDensity.regular,
+    Axis direction = Axis.horizontal,
+    bool wrap = false,
+    double? spacing,
+    double? runSpacing,
+    WrapAlignment alignment = WrapAlignment.start,
+    WrapAlignment runAlignment = WrapAlignment.start,
+    WrapCrossAlignment crossAxisAlignment = WrapCrossAlignment.center,
+    bool showDividers = false,
+    Color? dividerColor,
+    double? dividerThickness,
+    bool equalizeWidths = false,
+    String? semanticLabel,
+    Clip clipBehavior = Clip.none,
+  });
+}
+```
+
+Enums:
+```dart
+enum ButtonGroupM3EType { standard, connected }
+enum ButtonGroupM3EShape { round, square }
+enum ButtonGroupM3ESize { xs, sm, md, lg, xl }
+enum ButtonGroupM3EDensity { regular, compact }
+```
+
+## Scope for cooperative buttons
+
+The group exposes: `ButtonGroupM3EScope` and `ButtonGroupM3EItemScope`:
+
+```dart
+final g = ButtonGroupM3EScope.of(context);
+final i = ButtonGroupM3EItemScope.of(context);
+// g.size, g.shape, g.isConnected, g.direction ...
+// i.index, i.count, i.isFirst, i.isLast ...
+```
+
+Buttons can read these to adopt **height, corner radii (outer vs inner), compact paddings**, etc.
+
+## Defaults (recommended)
+
+- type: `standard`
+- shape: `round`
+- size: `md`
+- density: `regular`
+- direction: `Axis.horizontal`
+- wrap: `false`
+- standard spacing: token-based (≈8dp at md)
+- connected spacing: `0`
+- dividers: `false` by default (connected only)
+- dividerThickness: `1dp` (hairline)
+
+## Notes
+
+- In **wrap** mode, connected **dividers** are not auto-drawn per run (Flutter Wrap lacks per-run hooks). Use standard type, or accept flush seams.
+- `equalizeWidths` uses min-widths by size (40, 56, 72, 96, 120). For true equalization per run, implement a custom multi-pass layout if needed.
+- The widget does **not** clip children unless `clipBehavior` is set. Prefer cooperative styling via scope.
+
+## Example
+
+```dart
+ButtonGroupM3E(
+  type: ButtonGroupM3EType.connected,
+  shape: ButtonGroupM3EShape.round,
+  size: ButtonGroupM3ESize.lg,
+  showDividers: true,
+  semanticLabel: 'Playback controls',
+  children: [
+    // Your M3E buttons here...
+  ],
+)
+```

packages/button_group_m3e/lib/button_group_m3e.dart

@@ -0,0 +1,5 @@
+library button_group_m3e;
+
+export 'src/button_group_m3e_widget.dart';
+export 'src/button_group_m3e_enums.dart';
+export 'src/button_group_m3e_scope.dart' show ButtonGroupM3EScope, ButtonGroupM3EItemScope;

packages/button_group_m3e/lib/src/_tokens_adapter.dart

@@ -0,0 +1,44 @@
+import 'package:flutter/material.dart';
+import 'package:m3e_design/m3e_design.dart';
+import 'button_group_m3e_enums.dart';
+
+class _GroupMetrics {
+  final double spacing;
+  final double runSpacing;
+  final double dividerThickness;
+  const _GroupMetrics({required this.spacing, required this.runSpacing, required this.dividerThickness});
+}
+
+_GroupMetrics metricsFor(BuildContext context, ButtonGroupM3ESize size, ButtonGroupM3EDensity density) {
+  final m3e = Theme.of(context).extension<M3ETheme>() ?? M3ETheme.defaults(Theme.of(context).colorScheme);
+  final sp = m3e.spacing;
+
+  double space;
+  double run;
+  switch (size) {
+    case ButtonGroupM3ESize.xs: space = 6; run = 6; break;
+    case ButtonGroupM3ESize.sm: space = sp.sm; run = sp.sm; break;
+    case ButtonGroupM3ESize.md: space = sp.sm; run = sp.md; break;
+    case ButtonGroupM3ESize.lg: space = sp.md; run = sp.lg; break;
+    case ButtonGroupM3ESize.xl: space = sp.lg; run = sp.lg; break;
+  }
+
+  if (density == ButtonGroupM3EDensity.compact) {
+    space = (space * 0.75).floorToDouble();
+    run = (run * 0.75).floorToDouble();
+  }
+
+  return _GroupMetrics(spacing: space, runSpacing: run, dividerThickness: 1);
+}
+
+BorderRadius radiusFor(BuildContext context, ButtonGroupM3EShape shape, ButtonGroupM3ESize size) {
+  final m3e = Theme.of(context).extension<M3ETheme>() ?? M3ETheme.defaults(Theme.of(context).colorScheme);
+  final set = shape == ButtonGroupM3EShape.round ? m3e.shapes.round : m3e.shapes.square;
+  switch (size) {
+    case ButtonGroupM3ESize.xs: return set.xs;
+    case ButtonGroupM3ESize.sm: return set.sm;
+    case ButtonGroupM3ESize.md: return set.md;
+    case ButtonGroupM3ESize.lg: return set.lg;
+    case ButtonGroupM3ESize.xl: return set.xl;
+  }
+}

packages/button_group_m3e/lib/src/button_group_m3e_enums.dart

@@ -0,0 +1,4 @@
+enum ButtonGroupM3EType { standard, connected }
+enum ButtonGroupM3EShape { round, square }
+enum ButtonGroupM3ESize { xs, sm, md, lg, xl }
+enum ButtonGroupM3EDensity { regular, compact }

packages/button_group_m3e/lib/src/button_group_m3e_scope.dart

@@ -0,0 +1,64 @@
+import 'package:flutter/material.dart';
+import 'button_group_m3e_enums.dart';
+
+class ButtonGroupM3EScope extends InheritedWidget {
+  const ButtonGroupM3EScope({
+    super.key,
+    required super.child,
+    required this.type,
+    required this.shape,
+    required this.size,
+    required this.density,
+    required this.direction,
+    required this.isConnected,
+  });
+
+  final ButtonGroupM3EType type;
+  final ButtonGroupM3EShape shape;
+  final ButtonGroupM3ESize size;
+  final ButtonGroupM3EDensity density;
+  final Axis direction;
+  final bool isConnected;
+
+  static ButtonGroupM3EScope? maybeOf(BuildContext context) =>
+      context.dependOnInheritedWidgetOfExactType<ButtonGroupM3EScope>();
+  static ButtonGroupM3EScope of(BuildContext context) =>
+      maybeOf(context)!;
+
+  @override
+  bool updateShouldNotify(covariant ButtonGroupM3EScope oldWidget) =>
+      type != oldWidget.type ||
+      shape != oldWidget.shape ||
+      size != oldWidget.size ||
+      density != oldWidget.density ||
+      direction != oldWidget.direction ||
+      isConnected != oldWidget.isConnected;
+}
+
+class ButtonGroupM3EItemScope extends InheritedWidget {
+  const ButtonGroupM3EItemScope({
+    super.key,
+    required super.child,
+    required this.index,
+    required this.count,
+    required this.isFirst,
+    required this.isLast,
+  });
+
+  final int index;
+  final int count;
+  final bool isFirst;
+  final bool isLast;
+
+  static ButtonGroupM3EItemScope? maybeOf(BuildContext context) =>
+      context.dependOnInheritedWidgetOfExactType<ButtonGroupM3EItemScope>();
+  static ButtonGroupM3EItemScope of(BuildContext context) =>
+      maybeOf(context)!;
+
+  @override
+  bool updateShouldNotify(covariant ButtonGroupM3EItemScope oldWidget) =>
+      index != oldWidget.index ||
+      count != oldWidget.count ||
+      isFirst != oldWidget.isFirst ||
+      isLast != oldWidget.isLast;
+}

packages/button_group_m3e/lib/src/button_group_m3e_widget.dart

@@ -0,0 +1,186 @@
+import 'package:flutter/material.dart';
+import 'package:m3e_design/m3e_design.dart';
+import 'button_group_m3e_enums.dart';
+import '_tokens_adapter.dart';
+import 'button_group_m3e_scope.dart';
+
+class ButtonGroupM3E extends StatelessWidget {
+  const ButtonGroupM3E({
+    super.key,
+    required this.children,
+    this.type = ButtonGroupM3EType.standard,
+    this.shape = ButtonGroupM3EShape.round,
+    this.size = ButtonGroupM3ESize.md,
+    this.density = ButtonGroupM3EDensity.regular,
+    this.direction = Axis.horizontal,
+    this.wrap = false,
+    this.spacing,
+    this.runSpacing,
+    this.alignment = WrapAlignment.start,
+    this.runAlignment = WrapAlignment.start,
+    this.crossAxisAlignment = WrapCrossAlignment.center,
+    this.showDividers = false,
+    this.dividerColor,
+    this.dividerThickness,
+    this.equalizeWidths = false,
+    this.semanticLabel,
+    this.clipBehavior = Clip.none,
+  });
+
+  final List<Widget> children;
+
+  final ButtonGroupM3EType type;
+  final ButtonGroupM3EShape shape;
+  final ButtonGroupM3ESize size;
+  final ButtonGroupM3EDensity density;
+
+  final Axis direction;
+  final bool wrap;
+  final double? spacing;
+  final double? runSpacing;
+  final WrapAlignment alignment;
+  final WrapAlignment runAlignment;
+  final WrapCrossAlignment crossAxisAlignment;
+
+  final bool showDividers;
+  final Color? dividerColor;
+  final double? dividerThickness;
+  final bool equalizeWidths;
+
+  final String? semanticLabel;
+  final Clip clipBehavior;
+
+  bool get _connected => type == ButtonGroupM3EType.connected;
+
+  @override
+  Widget build(BuildContext context) {
+    final tokens = metricsFor(context, size, density);
+    final cs = Theme.of(context).colorScheme;
+    final dividerClr = dividerColor ?? cs.outlineVariant.withValues(alpha: 0.6);
+    final dividerThk = (dividerThickness ?? tokens.dividerThickness).clamp(0.5, 2.0);
+
+    final effSpacing = _connected ? 0.0 : (spacing ?? tokens.spacing);
+    final effRunSpacing = wrap ? (runSpacing ?? tokens.runSpacing) : 0.0;
+
+    final group = ButtonGroupM3EScope(
+      type: type,
+      shape: shape,
+      size: size,
+      density: density,
+      direction: direction,
+      isConnected: _connected,
+      child: _buildContent(context, effSpacing, effRunSpacing, dividerClr, dividerThk),
+    );
+
+    final semantics = Semantics(
+      container: true,
+      label: semanticLabel,
+      child: group,
+    );
+
+    if (clipBehavior == Clip.none) return semantics;
+    return ClipRRect(
+      clipBehavior: clipBehavior,
+      borderRadius: radiusFor(context, shape, size),
+      child: semantics,
+    );
+  }
+
+  Widget _buildContent(BuildContext context, double spacing, double runSpacing,
+      Color dividerColor, double dividerThickness) {
+    if (children.isEmpty) return const SizedBox.shrink();
+
+    if (wrap) {
+      return _wrapLayout(context, spacing, runSpacing);
+    }
+
+    final list = <Widget>[];
+    for (var i = 0; i < children.length; i++) {
+      final isFirst = i == 0;
+      final isLast = i == children.length - 1;
+
+      final child = _wrapItemScope(
+        context,
+        index: i,
+        count: children.length,
+        isFirst: isFirst,
+        isLast: isLast,
+        child: _maybeEqualized(children[i]),
+      );
+
+      list.add(child);
+
+      final isBetween = i < children.length - 1;
+      if (!isBetween) continue;
+
+      if (_connected) {
+        if (showDividers) {
+          list.add(_buildDivider(dividerColor, dividerThickness));
+        }
+      } else {
+        list.add(_spacer(spacing));
+      }
+    }
+
+    return direction == Axis.horizontal
+        ? Row(mainAxisSize: MainAxisSize.min, crossAxisAlignment: CrossAxisAlignment.center, children: list)
+        : Column(mainAxisSize: MainAxisSize.min, crossAxisAlignment: CrossAxisAlignment.center, children: list);
+  }
+
+  Widget _wrapLayout(BuildContext context, double spacing, double runSpacing) {
+    final wrapped = List<Widget>.generate(children.length, (i) {
+      final isFirst = i == 0;
+      final isLast = i == children.length - 1;
+      return _wrapItemScope(
+        context,
+        index: i,
+        count: children.length,
+        isFirst: isFirst,
+        isLast: isLast,
+        child: _maybeEqualized(children[i]),
+      );
+    });
+
+    return Wrap(
+      direction: direction,
+      spacing: spacing,
+      runSpacing: runSpacing,
+      alignment: alignment,
+      runAlignment: runAlignment,
+      crossAxisAlignment: crossAxisAlignment,
+      children: wrapped,
+    );
+  }
+
+  Widget _wrapItemScope(BuildContext context,
+      {required int index, required int count, required bool isFirst, required bool isLast, required Widget child}) {
+    return ButtonGroupM3EItemScope(
+      index: index,
+      count: count,
+      isFirst: isFirst,
+      isLast: isLast,
+      child: child,
+    );
+  }
+
+  Widget _spacer(double spacing) =>
+      direction == Axis.horizontal ? SizedBox(width: spacing) : SizedBox(height: spacing);
+
+  Widget _buildDivider(Color color, double thickness) {
+    return direction == Axis.horizontal
+        ? Container(width: thickness, height: 24, color: color)
+        : Container(height: thickness, width: 24, color: color);
+  }
+
+  Widget _maybeEqualized(Widget child) {
+    if (!equalizeWidths) return child;
+    final minW = switch (size) {
+      ButtonGroupM3ESize.xs => 40.0,
+      ButtonGroupM3ESize.sm => 56.0,
+      ButtonGroupM3ESize.md => 72.0,
+      ButtonGroupM3ESize.lg => 96.0,
+      ButtonGroupM3ESize.xl => 120.0,
+    };
+    return ConstrainedBox(constraints: BoxConstraints(minWidth: minW), child: child);
+  }
+}

packages/button_group_m3e/melos_button_group_m3e.iml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/example/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/android/.gradle" />
+      <excludeFolder url="file://$MODULE_DIR$/example/android/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/Flutter" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/Pods" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/Flutter" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/Pods" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/.symlinks" />
+    </content>
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="Dart SDK" level="project" />
+    <orderEntry type="library" name="Flutter Plugins" level="project" />
+    <orderEntry type="library" name="Dart Packages" level="project" />
+  </component>
+</module>

packages/button_group_m3e/pubspec.yaml

@@ -0,0 +1,18 @@
+name: button_group_m3e
+description: Wrapper-only Button Group for Material 3 Expressive (layout, shape, size propagation).
+version: 0.1.0
+publish_to: none
+repository: https://example.com/your-repo
+
+environment:
+  sdk: ">=3.5.0 <4.0.0"
+
+dependencies:
+  flutter:
+    sdk: flutter
+  m3e_design:
+    path: ../m3e_design
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter

packages/button_group_m3e/pubspec_overrides.yaml

@@ -0,0 +1,4 @@
+# melos_managed_dependency_overrides: m3e_design
+dependency_overrides:
+  m3e_design:
+    path: ..\\m3e_design

packages/button_group_m3e/test/button_group_m3e_test.dart

@@ -0,0 +1,7 @@
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  test('placeholder', () {
+    expect(1 + 2, 3);
+  });
+}

packages/button_m3e/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) ...
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

packages/button_m3e/README.md

@@ -0,0 +1,70 @@
+# button_m3e
+
+Material 3 **Expressive** Buttons for Flutter, built on top of Flutter's buttons but styled via **M3E** tokens.
+
+Variants: **filled**, **tonal**, **outlined**, **text**, **elevated**  
+Sizes: **small**, **medium**, **large**  
+Shape families: **round**, **square**  
+Density: **regular**, **compact**
+
+> Depends on `m3e_design` (ThemeExtension with colors/typography/spacing/shapes).
+
+## Monorepo Layout
+
+```
+packages/
+  m3e_design/
+  button_m3e/
+```
+
+In `pubspec.yaml` this package references `../m3e_design`.
+
+## Usage
+
+```dart
+import 'package:button_m3e/button_m3e.dart';
+
+ButtonM3E(
+  variant: ButtonM3EVariant.filled,
+  size: ButtonM3ESize.medium,
+  labelText: 'Continue',
+  leading: const Icon(Icons.arrow_forward),
+  onPressed: () {},
+);
+```
+
+Full-width button:
+
+```dart
+const ButtonM3E(
+  variant: ButtonM3EVariant.tonal,
+  size: ButtonM3ESize.large,
+  labelText: 'Buy now',
+  expand: true,
+);
+```
+
+Outlined/Text/Elevated work similarly.
+
+## Theming via `m3e_design`
+
+`button_m3e` reads tokens from your theme:
+
+- `m3e.colors.*` for background/foreground/border/disabled
+- `m3e.type.labelLarge` for the button label
+- `m3e.shapes.round|square` (uses `.lg` radius for buttons)
+- `m3e.spacing` for horizontal paddings (`sm`, `md`, `lg`)
+
+If the extension is not present, it falls back to `M3ETheme.defaults(ColorScheme)`.  
+You can still override `ThemeData.colorScheme` to influence defaults globally.
+
+## Notes
+
+- Label can be provided as `labelText` (String) or `label` (Widget).
+- `leading`/`trailing` are optional helpers for icons.
+- `expand: true` makes the button take full width.
+- `density: compact` slightly reduces height for each size.
+
+## License
+
+MIT

packages/button_m3e/lib/button_m3e.dart

@@ -0,0 +1,5 @@
+library button_m3e;
+
+export 'src/enums.dart';
+export 'src/button_m3e.dart';
+export 'src/button_theme_m3e.dart';

packages/button_m3e/lib/src/button_m3e.dart

@@ -0,0 +1,144 @@
+import 'package:flutter/material.dart';
+import 'enums.dart';
+import 'button_theme_m3e.dart';
+
+class ButtonM3E extends StatelessWidget {
+  const ButtonM3E({
+    super.key,
+    this.onPressed,
+    this.onLongPress,
+    this.leading,
+    this.trailing,
+    this.label,
+    this.labelText,
+    this.expand = false,
+    this.variant = ButtonM3EVariant.filled,
+    this.size = ButtonM3ESize.medium,
+    this.shapeFamily = ButtonM3EShapeFamily.round,
+    this.density = ButtonM3EDensity.regular,
+    this.semanticLabel,
+  }) : assert(label != null || labelText != null, 'Provide either label or labelText');
+
+  final VoidCallback? onPressed;
+  final VoidCallback? onLongPress;
+  final Widget? leading;
+  final Widget? trailing;
+  final Widget? label;
+  final String? labelText;
+  final bool expand;
+
+  final ButtonM3EVariant variant;
+  final ButtonM3ESize size;
+  final ButtonM3EShapeFamily shapeFamily;
+  final ButtonM3EDensity density;
+  final String? semanticLabel;
+
+  @override
+  Widget build(BuildContext context) {
+    final t = ButtonTokensAdapter(context);
+    final m = t.metrics(density);
+    final shape = t.shape(shapeFamily);
+
+    final (minH, pad) = switch (size) {
+      ButtonM3ESize.small => (m.heightSmall, m.paddingSmall),
+      ButtonM3ESize.medium => (m.heightMedium, m.paddingMedium),
+      ButtonM3ESize.large => (m.heightLarge, m.paddingLarge),
+    };
+
+    final style = _styleFor(context, t, shape, minH, pad);
+
+    final childLabel = label ?? Text(labelText!, overflow: TextOverflow.ellipsis);
+    final content = _buildContent(context, t, childLabel);
+
+    final Widget btn = switch (variant) {
+      ButtonM3EVariant.filled => FilledButton(style: style, onPressed: onPressed, onLongPress: onLongPress, child: content),
+      ButtonM3EVariant.tonal => FilledButton.tonal(style: style, onPressed: onPressed, onLongPress: onLongPress, child: content),
+      ButtonM3EVariant.outlined => OutlinedButton(style: style, onPressed: onPressed, onLongPress: onLongPress, child: content),
+      ButtonM3EVariant.text => TextButton(style: style, onPressed: onPressed, onLongPress: onLongPress, child: content),
+      ButtonM3EVariant.elevated => ElevatedButton(style: style, onPressed: onPressed, onLongPress: onLongPress, child: content),
+    };
+
+    if (!expand && semanticLabel == null) return btn;
+    final wrapped = expand ? SizedBox(width: double.infinity, child: btn) : btn;
+    if (semanticLabel == null) return wrapped;
+    return Semantics(
+      button: true,
+      label: semanticLabel,
+      child: wrapped,
+    );
+  }
+
+  ButtonStyle _styleFor(BuildContext context, ButtonTokensAdapter t, OutlinedBorder shape, double minH, EdgeInsetsGeometry pad) {
+    switch (variant) {
+      case ButtonM3EVariant.filled:
+        return FilledButton.styleFrom(
+          backgroundColor: t.bgFilled(),
+          foregroundColor: t.fgFilled(),
+          textStyle: t.labelStyle(),
+          minimumSize: Size(0, minH),
+          padding: pad,
+          shape: shape,
+        );
+      case ButtonM3EVariant.tonal:
+        return FilledButton.styleFrom(
+          backgroundColor: t.bgTonal(),
+          foregroundColor: t.fgTonal(),
+          textStyle: t.labelStyle(),
+          minimumSize: Size(0, minH),
+          padding: pad,
+          shape: shape,
+        );
+      case ButtonM3EVariant.outlined:
+        return OutlinedButton.styleFrom(
+          foregroundColor: t.fgOutlined(),
+          textStyle: t.labelStyle(),
+          minimumSize: Size(0, minH),
+          padding: pad,
+          shape: shape,
+          side: BorderSide(color: t.borderOutlined()),
+        );
+      case ButtonM3EVariant.text:
+        return TextButton.styleFrom(
+          foregroundColor: t.fgText(),
+          textStyle: t.labelStyle(),
+          minimumSize: Size(0, minH),
+          padding: pad,
+          shape: shape,
+        );
+      case ButtonM3EVariant.elevated:
+        return ElevatedButton.styleFrom(
+          backgroundColor: t.bgElevated(),
+          foregroundColor: t.fgElevated(),
+          textStyle: t.labelStyle(),
+          minimumSize: Size(0, minH),
+          padding: pad,
+          shape: shape,
+          elevation: _elevationFor(context, t),
+        );
+    }
+  }
+
+  double _elevationFor(BuildContext context, ButtonTokensAdapter t) {
+    // Simple mapping; can be themed further via tokens.
+    return 1.0;
+  }
+
+  Widget _buildContent(BuildContext context, ButtonTokensAdapter t, Widget childLabel) {
+    final style = t.labelStyle();
+    final text = DefaultTextStyle.merge(style: style, child: childLabel);
+    final hasLeading = leading != null;
+    final hasTrailing = trailing != null;
+
+    if (!hasLeading && !hasTrailing) return text;
+
+    return Row(
+      mainAxisSize: MainAxisSize.min,
+      mainAxisAlignment: MainAxisAlignment.center,
+      children: [
+        if (hasLeading) ...[leading!, const SizedBox(width: 8)],
+        Flexible(child: text),
+        if (hasTrailing) ...[const SizedBox(width: 8), trailing!],
+      ],
+    );
+  }
+}

packages/button_m3e/lib/src/button_m3e_widget.dart

@@ -0,0 +1,24 @@
+import 'package:flutter/material.dart';
+import 'package:m3e_design/m3e_design.dart';
+
+class ButtonM3EWidget extends StatelessWidget {
+  const ButtonM3EWidget({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    final m3e = context.m3e;
+    return Container(
+      padding: EdgeInsets.all(m3e.spacing.md),
+      decoration: BoxDecoration(
+        color: m3e.colors.surfaceStrong,
+        borderRadius: m3e.shapes.square.md,
+      ),
+      child: Text('Button placeholder', style: m3e.typography.base.labelLarge),
+    );
+  }
+}
+
+String _pascal(String s) => s
+    .split('_')
+    .map((p) => p.isEmpty ? '' : (p[0].toUpperCase() + p.substring(1)))
+    .join();

packages/button_m3e/lib/src/button_theme_m3e.dart

@@ -0,0 +1,94 @@
+import 'package:flutter/material.dart';
+import 'package:m3e_design/m3e_design.dart';
+
+import 'enums.dart';
+
+@immutable
+class _ButtonMetrics {
+  final double heightSmall;
+  final double heightMedium;
+  final double heightLarge;
+  final EdgeInsetsGeometry paddingSmall;
+  final EdgeInsetsGeometry paddingMedium;
+  final EdgeInsetsGeometry paddingLarge;
+  final BorderSide outlinedBorder;
+  final double elevation;
+  const _ButtonMetrics({
+    required this.heightSmall,
+    required this.heightMedium,
+    required this.heightLarge,
+    required this.paddingSmall,
+    required this.paddingMedium,
+    required this.paddingLarge,
+    required this.outlinedBorder,
+    required this.elevation,
+  });
+}
+
+_ButtonMetrics _metricsFor(BuildContext context, ButtonM3EDensity density) {
+  final theme = Theme.of(context);
+  final m3e =
+      theme.extension<M3ETheme>() ?? M3ETheme.defaults(theme.colorScheme);
+  final sp = m3e.spacing;
+
+  // Heights based on Material 3 expectations; tweakable by density.
+  double hS = 36;
+  double hM = 40;
+  double hL = 48;
+
+  if (density == ButtonM3EDensity.compact) {
+    hS -= 4;
+    hM -= 4;
+    hL -= 4;
+  }
+
+  return _ButtonMetrics(
+    heightSmall: hS,
+    heightMedium: hM,
+    heightLarge: hL,
+    paddingSmall: EdgeInsets.symmetric(horizontal: sp.sm),
+    paddingMedium: EdgeInsets.symmetric(horizontal: sp.md),
+    paddingLarge: EdgeInsets.symmetric(horizontal: sp.lg),
+    outlinedBorder: BorderSide(color: m3e.colors.outline, width: 1.0),
+    elevation: 1.0,
+  );
+}
+
+class ButtonTokensAdapter {
+  ButtonTokensAdapter(this.context);
+  final BuildContext context;
+
+  M3ETheme get _m3e {
+    final t = Theme.of(context);
+    return t.extension<M3ETheme>() ?? M3ETheme.defaults(t.colorScheme);
+  }
+
+  // Colors
+  Color bgFilled() => _m3e.colors.primary;
+  Color fgFilled() => _m3e.colors.onPrimary;
+  Color bgTonal() => _m3e.colors.secondaryContainer;
+  Color fgTonal() => _m3e.colors.onSecondaryContainer;
+  Color bgElevated() => _m3e.colors.surfaceContainerLowest;
+  Color fgElevated() => _m3e.colors.primary;
+  Color fgText() => _m3e.colors.primary;
+  Color borderOutlined() => _m3e.colors.outline;
+  Color fgOutlined() => _m3e.colors.primary;
+  Color disabledFg() => _m3e.colors.onSurface.withValues(alpha: 0.38);
+  Color disabledBg() => _m3e.colors.onSurface.withValues(alpha: 0.12);
+
+  // Typography
+  TextStyle labelStyle() => _m3e.type.labelLarge;
+
+  // Shapes
+  OutlinedBorder shape(ButtonM3EShapeFamily family) {
+    if (family == ButtonM3EShapeFamily.round) {
+      return RoundedRectangleBorder(borderRadius: _m3e.shapes.round.lg);
+    }
+    // Square family should have sharp corners (no rounding)
+    return const RoundedRectangleBorder(borderRadius: BorderRadius.zero);
+  }
+
+  // Spacing & heights
+  _ButtonMetrics metrics(ButtonM3EDensity density) =>
+      _metricsFor(context, density);
+}

packages/button_m3e/lib/src/enums.dart

@@ -0,0 +1,4 @@
+enum ButtonM3EVariant { filled, tonal, outlined, text, elevated }
+enum ButtonM3ESize { small, medium, large }
+enum ButtonM3EShapeFamily { round, square }
+enum ButtonM3EDensity { regular, compact }

packages/button_m3e/melos_button_m3e.iml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/example/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/android/.gradle" />
+      <excludeFolder url="file://$MODULE_DIR$/example/android/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/Flutter" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/Pods" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/Flutter" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/Pods" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/.symlinks" />
+    </content>
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="Dart SDK" level="project" />
+    <orderEntry type="library" name="Flutter Plugins" level="project" />
+    <orderEntry type="library" name="Dart Packages" level="project" />
+  </component>
+</module>

packages/button_m3e/pubspec.yaml

@@ -0,0 +1,18 @@
+name: button_m3e
+description: Material 3 Expressive Buttons for Flutter (filled, tonal, outlined, text, elevated) with M3E tokens.
+version: 0.1.0
+publish_to: none
+
+environment:
+  sdk: ">=3.5.0 <4.0.0"
+  flutter: ">=3.22.0"
+
+dependencies:
+  flutter:
+    sdk: flutter
+  m3e_design:
+    path: ../m3e_design
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter

packages/button_m3e/pubspec_overrides.yaml

@@ -0,0 +1,4 @@
+# melos_managed_dependency_overrides: m3e_design
+dependency_overrides:
+  m3e_design:
+    path: ..\\m3e_design

packages/button_m3e/test/button_m3e_test.dart

@@ -0,0 +1,7 @@
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  test('placeholder', () {
+    expect(1 + 1, 2);
+  });
+}

packages/fab_m3e/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) ...
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

packages/fab_m3e/README.md

@@ -0,0 +1,93 @@
+# fab_m3e
+
+Material 3 **Expressive** Floating Action Buttons for Flutter:
+
+- **FabM3E**: circular FAB (small / regular / large)
+- **ExtendedFabM3E**: pill-shaped FAB with label (and optional icon)
+- **FabMenuM3E**: FAB menu (speed dial) with animated items (up/down/left/right)
+
+All components read **M3E tokens** from `m3e_design` (ThemeExtension).
+
+## Monorepo Layout
+
+```
+packages/
+  m3e_design/
+  fab_m3e/
+```
+
+This package's `pubspec.yaml` references `../m3e_design`.
+
+## Usage
+
+### FAB
+
+```dart
+import 'package:fab_m3e/fab_m3e.dart';
+
+FabM3E(
+  icon: const Icon(Icons.add),
+  kind: FabM3EKind.primary,
+  size: FabM3ESize.regular,
+  onPressed: () {},
+);
+```
+
+### Extended FAB
+
+```dart
+ExtendedFabM3E(
+  icon: const Icon(Icons.edit),
+  label: const Text('Compose'),
+  kind: FabM3EKind.secondary,
+  onPressed: () {},
+);
+```
+
+### FAB Menu (Speed dial)
+
+```dart
+final controller = FabMenuController();
+
+FabMenuM3E(
+  controller: controller,
+  alignment: Alignment.bottomRight,
+  direction: FabMenuDirection.up,
+  primaryFab: FabM3E(icon: const Icon(Icons.add), onPressed: controller.toggle),
+  items: [
+    FabMenuItem(
+      icon: const Icon(Icons.photo),
+      label: const Text('Photo'),
+      onPressed: () {},
+    ),
+    FabMenuItem(
+      icon: const Icon(Icons.note),
+      label: const Text('Note'),
+      onPressed: () {},
+    ),
+  ],
+);
+```
+
+## Theming via `m3e_design`
+
+- Background/foreground colors derive from kind:
+  - `primary` → `primaryContainer` / `onPrimaryContainer`
+  - `secondary` → `secondaryContainer` / `onSecondaryContainer`
+  - `tertiary` → `tertiaryContainer` / `onTertiaryContainer`
+  - `surface` → `surfaceContainerHigh` / `onSurface`
+- Sizes: **small ≈40dp**, **regular ≈56dp**, **large ≈96dp**
+- Extended FAB height ≈56dp
+- Elevations: rest 6, hover 8, pressed 12 (tweak in code or via tokens)
+- Shapes: `round`/`square` from `m3e_design.shapes` (extended uses StadiumBorder)
+
+## Notes
+
+- `FabM3E` uses `RawMaterialButton` to directly inject shape/elevation/colors with tokens.
+- `ExtendedFabM3E` uses `Material` + `InkWell` with stadium shape and token paddings.
+- `FabMenuM3E` stacks items near the primary FAB and animates **scale + fade**.
+- Provide your own `Hero` tags if coordinating transitions across pages.
+
+## License
+
+MIT

packages/fab_m3e/lib/fab_m3e.dart

@@ -0,0 +1,7 @@
+library fab_m3e;
+
+export 'src/enums.dart';
+export 'src/fab_theme_m3e.dart' show FabTokensAdapter;
+export 'src/fab_m3e.dart';
+export 'src/extended_fab_m3e.dart';
+export 'src/fab_menu_m3e.dart';

packages/fab_m3e/lib/src/enums.dart

@@ -0,0 +1,8 @@
+enum FabM3EKind { primary, secondary, tertiary, surface }
+/// Size mapping follows Material 3: small (≈40), regular (≈56), large (≈96).
+enum FabM3ESize { small, regular, large }
+enum FabM3EShapeFamily { round, square }
+enum FabM3EDensity { regular, compact }
+
+/// Direction for the FAB menu children to expand.
+enum FabMenuDirection { up, down, left, right }

packages/fab_m3e/lib/src/extended_fab_m3e.dart

@@ -0,0 +1,93 @@
+import 'package:flutter/material.dart';
+
+import 'enums.dart';
+import 'fab_theme_m3e.dart';
+
+class ExtendedFabM3E extends StatelessWidget {
+  const ExtendedFabM3E({
+    super.key,
+    required this.label,
+    this.icon,
+    this.onPressed,
+    this.tooltip,
+    this.heroTag,
+    this.kind = FabM3EKind.primary,
+    this.size = FabM3ESize.regular,
+    this.shapeFamily = FabM3EShapeFamily.round,
+    this.density = FabM3EDensity.regular,
+    this.elevation,
+    this.expand = false,
+    this.semanticLabel,
+  });
+
+  final Widget label;
+  final Widget? icon;
+  final VoidCallback? onPressed;
+  final String? tooltip;
+  final Object? heroTag;
+  final FabM3EKind kind;
+  final FabM3ESize size;
+  final FabM3EShapeFamily shapeFamily;
+  final FabM3EDensity density;
+  final double? elevation;
+  final bool expand;
+  final String? semanticLabel;
+
+  @override
+  Widget build(BuildContext context) {
+    final tokens = FabTokensAdapter(context);
+    final m = tokens.metrics(density);
+    final bg = tokens.bg(kind);
+    final fg = tokens.fg(kind);
+    final shape = tokens.shape(shapeFamily, size, extended: true);
+
+    final minH = m.extendedHeight;
+    final child = DefaultTextStyle.merge(
+      style: tokens.labelStyle().copyWith(color: fg),
+      child: Row(
+        mainAxisSize: MainAxisSize.min,
+        children: [
+          if (icon != null) ...[
+            IconTheme.merge(
+                data: IconThemeData(color: fg, size: m.iconSize), child: icon!),
+            const SizedBox(width: 12)
+          ],
+          Flexible(child: label),
+        ],
+      ),
+    );
+
+    final btn = ConstrainedBox(
+      constraints: BoxConstraints(minHeight: minH),
+      child: Material(
+        shape: shape,
+        color: bg,
+        elevation: elevation ?? m.elevationRest,
+        clipBehavior: Clip.antiAlias,
+        child: InkWell(
+          onTap: onPressed,
+          onHover: (_) {},
+          child: Padding(
+            padding: m.extendedPadding,
+            child: Align(alignment: Alignment.center, child: child),
+          ),
+        ),
+      ),
+    );
+
+    final core = Tooltip(
+      message: tooltip ?? '',
+      preferBelow: false,
+      child: expand ? SizedBox(width: double.infinity, child: btn) : btn,
+    );
+
+    Widget wrapped = core;
+    if (heroTag != null &&
+        context.findAncestorWidgetOfExactType<Hero>() == null) {
+      wrapped = Hero(tag: heroTag!, child: core);
+    }
+
+    if (semanticLabel == null) return wrapped;
+    return Semantics(button: true, label: semanticLabel, child: wrapped);
+  }
+}

packages/fab_m3e/lib/src/fab_m3e.dart

@@ -0,0 +1,88 @@
+import 'package:flutter/material.dart';
+
+import 'enums.dart';
+import 'fab_theme_m3e.dart';
+
+class FabM3E extends StatelessWidget {
+  const FabM3E({
+    super.key,
+    required this.icon,
+    this.onPressed,
+    this.tooltip,
+    this.heroTag,
+    this.kind = FabM3EKind.primary,
+    this.size = FabM3ESize.regular,
+    this.shapeFamily = FabM3EShapeFamily.round,
+    this.density = FabM3EDensity.regular,
+    this.elevation,
+    this.focusNode,
+    this.autofocus = false,
+    this.isPrimaryAction = true,
+    this.semanticLabel,
+  });
+
+  final Widget icon;
+  final VoidCallback? onPressed;
+  final String? tooltip;
+  final Object? heroTag;
+  final FabM3EKind kind;
+  final FabM3ESize size;
+  final FabM3EShapeFamily shapeFamily;
+  final FabM3EDensity density;
+  final double? elevation;
+  final FocusNode? focusNode;
+  final bool autofocus;
+  final bool isPrimaryAction;
+  final String? semanticLabel;
+
+  @override
+  Widget build(BuildContext context) {
+    final tokens = FabTokensAdapter(context);
+    final m = tokens.metrics(density);
+    final bg = tokens.bg(kind);
+    final fg = tokens.fg(kind);
+    final shape = tokens.shape(shapeFamily, size);
+    final double dim = switch (size) {
+      FabM3ESize.small => m.small,
+      FabM3ESize.regular => m.regular,
+      FabM3ESize.large => m.large,
+    };
+
+    final button = SizedBox(
+      width: dim,
+      height: dim,
+      child: RawMaterialButton(
+        onPressed: onPressed,
+        fillColor: bg,
+        elevation: elevation ?? m.elevationRest,
+        hoverElevation: m.elevationHover,
+        highlightElevation: m.elevationPressed,
+        focusElevation: m.elevationHover,
+        shape: shape,
+        focusNode: focusNode,
+        autofocus: autofocus,
+        clipBehavior: Clip.antiAlias,
+        child: IconTheme.merge(
+          data: IconThemeData(color: fg, size: m.iconSize),
+          child: icon,
+        ),
+      ),
+    );
+
+    final core = Tooltip(
+      message: tooltip ?? '',
+      preferBelow: false,
+      child: button,
+    );
+
+    // Only wrap with Hero when an explicit tag is provided and there is no ancestor hero.
+    Widget wrapped = core;
+    if (heroTag != null &&
+        context.findAncestorWidgetOfExactType<Hero>() == null) {
+      wrapped = Hero(tag: heroTag!, child: core);
+    }
+
+    if (semanticLabel == null) return wrapped;
+    return Semantics(button: true, label: semanticLabel, child: wrapped);
+  }
+}

packages/fab_m3e/lib/src/fab_m3e_widget.dart

@@ -0,0 +1,21 @@
+import 'package:flutter/material.dart';
+import 'package:m3e_design/m3e_design.dart';
+
+class FabM3EWidget extends StatelessWidget {
+  const FabM3EWidget({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    final m3e = context.m3e;
+    return Container(
+      padding: EdgeInsets.all(m3e.spacing.md),
+      decoration: BoxDecoration(
+        color: m3e.colors.surfaceStrong,
+        borderRadius: m3e.shapes.square.md,
+      ),
+      child: Text('Fab placeholder', style: m3e.typography.base.titleMedium),
+    );
+  }
+}
+
+String _pascal(String s) => s.split('_').map((p) => p.isEmpty ? '' : (p[0].toUpperCase() + p.substring(1))).join();

packages/fab_m3e/lib/src/fab_menu_m3e.dart

@@ -0,0 +1,247 @@
+import 'package:flutter/material.dart';
+import 'package:m3e_design/m3e_design.dart';
+
+import 'enums.dart';
+import 'extended_fab_m3e.dart';
+
+class FabMenuItem {
+  FabMenuItem({
+    required this.icon,
+    required this.label,
+    required this.onPressed,
+    this.semanticLabel,
+  });
+
+  final Widget icon;
+  final Widget label;
+  final VoidCallback onPressed;
+  final String? semanticLabel;
+}
+
+class FabMenuController extends ChangeNotifier {
+  bool _open = false;
+  bool get isOpen => _open;
+  void open() {
+    if (!_open) {
+      _open = true;
+      notifyListeners();
+    }
+  }
+
+  void close() {
+    if (_open) {
+      _open = false;
+      notifyListeners();
+    }
+  }
+
+  void toggle() {
+    _open = !_open;
+    notifyListeners();
+  }
+}
+
+class FabMenuM3E extends StatefulWidget {
+  const FabMenuM3E({
+    super.key,
+    required this.primaryFab,
+    required this.items,
+    this.direction = FabMenuDirection.up,
+    this.spacing,
+    this.overlay = true,
+    this.overlayColor,
+    this.controller,
+    this.alignment = Alignment.bottomRight,
+    this.popOnItemTap = true,
+    this.heroTag,
+  });
+
+  /// The FAB that toggles the menu (typically a primary FabM3E or ExtendedFabM3E).
+  final Widget primaryFab;
+
+  /// Menu items displayed when open.
+  final List<FabMenuItem> items;
+
+  /// Direction in which children expand.
+  final FabMenuDirection direction;
+
+  /// Spacing between items.
+  final double? spacing;
+
+  /// Show a scrim overlay behind the menu when open.
+  final bool overlay;
+  final Color? overlayColor;
+
+  /// Optional external controller; if omitted, an internal one is created.
+  final FabMenuController? controller;
+
+  /// Alignment within the Stack (e.g., bottomRight in a Scaffold).
+  final Alignment alignment;
+
+  /// Whether to automatically close the menu when an item is tapped.
+  final bool popOnItemTap;
+
+  final Object? heroTag;
+
+  @override
+  State<FabMenuM3E> createState() => _FabMenuM3EState();
+}
+
+class _FabMenuM3EState extends State<FabMenuM3E>
+    with SingleTickerProviderStateMixin {
+  late final FabMenuController _controller =
+      widget.controller ?? FabMenuController();
+  late final AnimationController _anim = AnimationController(
+    vsync: this,
+    duration: const Duration(milliseconds: 200),
+    reverseDuration: const Duration(milliseconds: 150),
+  );
+  late final Animation<double> _scale = CurvedAnimation(
+      parent: _anim,
+      curve: Curves.easeOutCubic,
+      reverseCurve: Curves.easeInCubic);
+
+  @override
+  void initState() {
+    super.initState();
+    _controller.addListener(_onChange);
+  }
+
+  @override
+  void dispose() {
+    _controller.removeListener(_onChange);
+    if (widget.controller == null) _controller.dispose();
+    _anim.dispose();
+    super.dispose();
+  }
+
+  void _onChange() {
+    if (_controller.isOpen) {
+      _anim.forward();
+    } else {
+      _anim.reverse();
+    }
+    setState(() {});
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final sp = context.m3e.spacing; // use spacing scale via context extension
+    final gap = widget.spacing ?? sp.md;
+
+    final children = <Widget>[];
+
+    for (int i = 0; i < widget.items.length; i++) {
+      final item = widget.items[i];
+      final w = _buildMenuItem(context, item);
+      final animatedChild = ScaleTransition(
+        scale: _scale,
+        child: FadeTransition(
+          opacity: _scale,
+          child: w,
+        ),
+      );
+      // Ensure Positioned is a direct child of the Stack
+      children.add(_positioned(animatedChild, i, gap));
+    }
+
+    final menu = Stack(
+      alignment: widget.alignment,
+      clipBehavior: Clip.none,
+      children: [
+        // Primary FAB
+        Align(
+          alignment: widget.alignment,
+          child: _wrapToggle(widget.primaryFab),
+        ),
+        // Menu items
+        ...children,
+      ],
+    );
+
+    final overlay = widget.overlay && _controller.isOpen
+        ? Positioned.fill(
+            child: GestureDetector(
+              onTap: _controller.toggle,
+              child: ColoredBox(
+                color:
+                    widget.overlayColor ?? Colors.black.withValues(alpha: 0.25),
+              ),
+            ),
+          )
+        : const SizedBox.shrink();
+
+    return Stack(
+      children: [
+        overlay,
+        Positioned.fill(
+            child: IgnorePointer(
+                ignoring: !_controller.isOpen, child: Container())),
+        menu,
+      ],
+    );
+  }
+
+  Widget _wrapToggle(Widget child) {
+    final core = GestureDetector(
+      onTap: _controller.toggle,
+      behavior: HitTestBehavior.opaque,
+      child: child,
+    );
+
+    if (widget.heroTag != null && context.findAncestorWidgetOfExactType<Hero>() == null) {
+      return Hero(tag: widget.heroTag!, child: core);
+    }
+    return core;
+  }
+
+  Widget _positioned(Widget child, int index, double gap) {
+    final offset = (index + 1) *
+        (gap +
+            56); // base step; extended affects height, but 56 is a practical default
+    switch (widget.direction) {
+      case FabMenuDirection.up:
+        return Positioned(
+          right: 0,
+          bottom: offset,
+          child: child,
+        );
+      case FabMenuDirection.down:
+        return Positioned(
+          right: 0,
+          top: offset,
+          child: child,
+        );
+      case FabMenuDirection.left:
+        return Positioned(
+          right: offset,
+          bottom: 0,
+          child: child,
+        );
+      case FabMenuDirection.right:
+        return Positioned(
+          left: offset,
+          bottom: 0,
+          child: child,
+        );
+    }
+  }
+
+  Widget _buildMenuItem(BuildContext context, FabMenuItem item) {
+    return Padding(
+      padding: const EdgeInsets.symmetric(vertical: 2.0),
+      child: ExtendedFabM3E(
+        icon: item.icon,
+        label: item.label,
+        onPressed: () {
+          item.onPressed();
+          if (widget.popOnItemTap) _controller.close();
+        },
+        kind: FabM3EKind.surface,
+        size: FabM3ESize.regular,
+        density: FabM3EDensity.regular,
+        semanticLabel: item.semanticLabel,
+      ),
+    );
+  }
+}

packages/fab_m3e/lib/src/fab_theme_m3e.dart

@@ -0,0 +1,106 @@
+import 'package:flutter/material.dart';
+import 'package:m3e_design/m3e_design.dart';
+import 'enums.dart';
+
+@immutable
+class _FabMetrics {
+  final double small;
+  final double regular;
+  final double large;
+  final double extendedHeight;
+  final EdgeInsetsGeometry extendedPadding;
+  final double iconSize;
+  final double elevationRest;
+  final double elevationHover;
+  final double elevationPressed;
+  const _FabMetrics({
+    required this.small,
+    required this.regular,
+    required this.large,
+    required this.extendedHeight,
+    required this.extendedPadding,
+    required this.iconSize,
+    required this.elevationRest,
+    required this.elevationHover,
+    required this.elevationPressed,
+  });
+}
+
+_FabMetrics _metricsFor(BuildContext context, FabM3EDensity density) {
+  final theme = Theme.of(context);
+  final m3e = theme.extension<M3ETheme>() ?? M3ETheme.defaults(theme.colorScheme);
+  final sp = m3e.spacing;
+
+  double small = 40;
+  double regular = 56;
+  double large = 96;
+  double extH = 56;
+  double icon = 24;
+
+  if (density == FabM3EDensity.compact) {
+    small -= 4; regular -= 4; large -= 4; extH -= 4;
+  }
+
+  return _FabMetrics(
+    small: small,
+    regular: regular,
+    large: large,
+    extendedHeight: extH,
+    extendedPadding: EdgeInsets.symmetric(horizontal: sp.lg),
+    iconSize: icon,
+    elevationRest: 6.0,
+    elevationHover: 8.0,
+    elevationPressed: 12.0,
+  );
+}
+
+class FabTokensAdapter {
+  FabTokensAdapter(this.context);
+  final BuildContext context;
+
+  M3ETheme get _m3e {
+    final t = Theme.of(context);
+    return t.extension<M3ETheme>() ?? M3ETheme.defaults(t.colorScheme);
+  }
+
+  _FabMetrics metrics(FabM3EDensity density) => _metricsFor(context, density);
+
+  // Colors by kind
+  Color bg(FabM3EKind kind) {
+    switch (kind) {
+      case FabM3EKind.primary:
+        return _m3e.colors.primaryContainer;
+      case FabM3EKind.secondary:
+        return _m3e.colors.secondaryContainer;
+      case FabM3EKind.tertiary:
+        return _m3e.colors.tertiaryContainer;
+      case FabM3EKind.surface:
+        return _m3e.colors.surfaceContainerHigh;
+    }
+  }
+
+  Color fg(FabM3EKind kind) {
+    switch (kind) {
+      case FabM3EKind.primary:
+        return _m3e.colors.onPrimaryContainer;
+      case FabM3EKind.secondary:
+        return _m3e.colors.onSecondaryContainer;
+      case FabM3EKind.tertiary:
+        return _m3e.colors.onTertiaryContainer;
+      case FabM3EKind.surface:
+        return _m3e.colors.onSurface;
+    }
+  }
+
+  // Shapes
+  ShapeBorder shape(FabM3EShapeFamily family, FabM3ESize size, {bool extended = false}) {
+    final set = family == FabM3EShapeFamily.round ? _m3e.shapes.round : _m3e.shapes.square;
+    if (extended) return StadiumBorder(side: BorderSide.none);
+    // circular-ish fab: use large radius to approach circle; actual size enforced by constraints
+    final radius = switch (size) { FabM3ESize.small => set.lg, FabM3ESize.regular => set.xl, FabM3ESize.large => set.xl };
+    return RoundedRectangleBorder(borderRadius: radius);
+  }
+
+  // Typography
+  TextStyle labelStyle() => _m3e.type.labelLarge;
+}

packages/fab_m3e/melos_fab_m3e.iml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/example/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/android/.gradle" />
+      <excludeFolder url="file://$MODULE_DIR$/example/android/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/Flutter" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/Pods" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/Flutter" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/Pods" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/.symlinks" />
+    </content>
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="Dart SDK" level="project" />
+    <orderEntry type="library" name="Flutter Plugins" level="project" />
+    <orderEntry type="library" name="Dart Packages" level="project" />
+  </component>
+</module>

packages/fab_m3e/pubspec.yaml

@@ -0,0 +1,18 @@
+name: fab_m3e
+description: Material 3 Expressive Floating Action Button (FAB), Extended FAB, and FAB Menu for Flutter using M3E tokens.
+version: 0.1.0
+publish_to: none
+
+environment:
+  sdk: ">=3.5.0 <4.0.0"
+  flutter: ">=3.22.0"
+
+dependencies:
+  flutter:
+    sdk: flutter
+  m3e_design:
+    path: ../m3e_design
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter

packages/fab_m3e/pubspec_overrides.yaml

@@ -0,0 +1,4 @@
+# melos_managed_dependency_overrides: m3e_design
+dependency_overrides:
+  m3e_design:
+    path: ..\\m3e_design

packages/fab_m3e/test/fab_m3e_test.dart

@@ -0,0 +1,7 @@
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  test('placeholder', () {
+    expect(3 * 3, 9);
+  });
+}

packages/icon_button_m3e/README.md

@@ -0,0 +1,92 @@
+# icon_button_m3e
+
+Expressive Material 3 icon button for Flutter — `IconButtonM3E` — with
+five sizes (XS–XL), four variants (standard, filled, tonal, outlined),
+round/square shapes, toggle support, and guaranteed 48×48dp tap targets
+(even when visual size is 32/40).
+
+## Highlights
+
+- Sizes: `M3EIconButtonSize` = XS, SM, MD, LG, XL
+- Widths: `M3EIconButtonWidth` = default, narrow, wide
+- Variants: standard, filled, tonal, outlined
+- Shapes: round (pill) or square (rounded rect)
+- Toggle: `isSelected` + `selectedIcon`
+- A11y: min 48×48dp hit target; semantics label/selected state
+- Tokens: centralized static values in `M3EIconButtonTokens` (no ThemeExtension)
+
+## Install
+
+```yaml
+dependencies:
+  icon_button_m3e:
+    path: ../icon_button_m3e  # or from pub once published
+```
+
+## Quick Start
+
+```dart
+import 'package:icon_button_m3e/icon_button_m3e.dart';
+
+IconButtonM3E(
+  variant: IconButtonM3EVariant.filled,
+  size: M3EIconButtonSize.md,
+  width: M3EIconButtonWidth.defaultWidth,
+  icon: const Icon(Icons.mic),
+  tooltip: 'Start recording',
+  onPressed: () {},
+);
+```
+
+### Toggle
+
+```dart
+bool isFav = false;
+
+IconButtonM3E(
+  variant: IconButtonM3EVariant.tonal,
+  isSelected: isFav,
+  icon: const Icon(Icons.favorite_border),
+  selectedIcon: const Icon(Icons.favorite),
+  tooltip: isFav ? 'Remove from favorites' : 'Add to favorites',
+  onPressed: () => setState(() => isFav = !isFav),
+);
+```
+
+## Sizing
+
+- Visual container sizes come from tokens: `M3EIconButtonTokens.visual[size][width]`.
+- Minimum interactive target sizes come from `M3EIconButtonTokens.target[size][width]`.
+  - XS/SM enforce at least 48×48; others match their visual sizes.
+- Icon glyph sizes are in `M3EIconButtonTokens.icon[size]`.
+
+For example (default width):
+- XS: 32×32 visual, 48×48 target
+- SM: 40×40 visual, 48×48 target (SM wide: 52×48)
+- MD: 56×56
+- LG: 96×96
+- XL: 136×136
+
+## Colors and shapes
+
+- Colors are derived from your `ThemeData.colorScheme`:
+  - standard: transparent bg, onSurfaceVariant fg (selected uses primary)
+  - filled: primary bg, onPrimary fg
+  - tonal: secondaryContainer bg, onSecondaryContainer fg
+  - outlined: transparent bg, primary fg, outline border
+- Shapes: `M3EIconButtonShapeVariant.round` (pill) or `.square` (rounded square).
+  - Pressed state uses a shared, more-square radius per size.
+  - If used as a toggle, selected state flips round/square for expressive feel.
+
+## Example
+
+Run the example app:
+
+```sh
+cd example
+flutter run
+```
+
+## License
+
+MIT

packages/icon_button_m3e/example/.gitignore

@@ -0,0 +1,45 @@
+# Miscellaneous
+*.class
+*.log
+*.pyc
+*.swp
+.DS_Store
+.atom/
+.build/
+.buildlog/
+.history
+.svn/
+.swiftpm/
+migrate_working_dir/
+
+# IntelliJ related
+*.iml
+*.ipr
+*.iws
+.idea/
+
+# The .vscode folder contains launch configuration and tasks you configure in
+# VS Code which you may wish to be included in version control, so this line
+# is commented out by default.
+#.vscode/
+
+# Flutter/Dart/Pub related
+**/doc/api/
+**/ios/Flutter/.last_build_id
+.dart_tool/
+.flutter-plugins-dependencies
+.pub-cache/
+.pub/
+/build/
+/coverage/
+
+# Symbolication related
+app.*.symbols
+
+# Obfuscation related
+app.*.map.json
+
+# Android Studio will place build artifacts here
+/android/app/debug
+/android/app/profile
+/android/app/release

packages/icon_button_m3e/example/.metadata

@@ -0,0 +1,45 @@
+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled and should not be manually edited.
+
+version:
+  revision: "d693b4b9dbac2acd4477aea4555ca6dcbea44ba2"
+  channel: "stable"
+
+project_type: app
+
+# Tracks metadata for the flutter migrate command
+migration:
+  platforms:
+    - platform: root
+      create_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+      base_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+    - platform: android
+      create_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+      base_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+    - platform: ios
+      create_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+      base_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+    - platform: linux
+      create_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+      base_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+    - platform: macos
+      create_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+      base_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+    - platform: web
+      create_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+      base_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+    - platform: windows
+      create_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+      base_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+
+  # User provided section
+
+  # List of Local paths (relative to this file) that should be
+  # ignored by the migrate tool.
+  #
+  # Files that are not part of the templates will be ignored by default.
+  unmanaged_files:
+    - 'lib/main.dart'
+    - 'ios/Runner.xcodeproj/project.pbxproj'

packages/icon_button_m3e/example/README.md

@@ -0,0 +1,16 @@
+# icon_button_m3e_example
+
+A new Flutter project.
+
+## Getting Started
+
+This project is a starting point for a Flutter application.
+
+A few resources to get you started if this is your first Flutter project:
+
+- [Lab: Write your first Flutter app](https://docs.flutter.dev/get-started/codelab)
+- [Cookbook: Useful Flutter samples](https://docs.flutter.dev/cookbook)
+
+For help getting started with Flutter development, view the
+[online documentation](https://docs.flutter.dev/), which offers tutorials,
+samples, guidance on mobile development, and a full API reference.

packages/icon_button_m3e/example/analysis_options.yaml

@@ -0,0 +1,28 @@
+# This file configures the analyzer, which statically analyzes Dart code to
+# check for errors, warnings, and lints.
+#
+# The issues identified by the analyzer are surfaced in the UI of Dart-enabled
+# IDEs (https://dart.dev/tools#ides-and-editors). The analyzer can also be
+# invoked from the command line by running `flutter analyze`.
+
+# The following line activates a set of recommended lints for Flutter apps,
+# packages, and plugins designed to encourage good coding practices.
+include: package:flutter_lints/flutter.yaml
+
+linter:
+  # The lint rules applied to this project can be customized in the
+  # section below to disable rules from the `package:flutter_lints/flutter.yaml`
+  # included above or to enable additional rules. A list of all available lints
+  # and their documentation is published at https://dart.dev/lints.
+  #
+  # Instead of disabling a lint rule for the entire project in the
+  # section below, it can also be suppressed for a single line of code
+  # or a specific dart file by using the `// ignore: name_of_lint` and
+  # `// ignore_for_file: name_of_lint` syntax on the line or in the file
+  # producing the lint.
+  rules:
+    # avoid_print: false  # Uncomment to disable the `avoid_print` rule
+    # prefer_single_quotes: true  # Uncomment to enable the `prefer_single_quotes` rule
+
+# Additional information about this file can be found at
+# https://dart.dev/guides/language/analysis-options

packages/icon_button_m3e/example/lib/main.dart

@@ -0,0 +1,183 @@
+import 'package:flutter/material.dart';
+import 'package:icon_button_m3e/icon_button_m3e.dart';
+
+void main() => runApp(const DemoApp());
+
+class DemoApp extends StatelessWidget {
+  const DemoApp({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      debugShowCheckedModeBanner: false,
+      title: 'IconButtonM3E Demo',
+      theme: ThemeData(
+        useMaterial3: true,
+        colorScheme: ColorScheme.fromSeed(seedColor: Colors.indigo),
+/*        extensions: const [IconButtonM3ETokens.fallback()],*/
+      ),
+      home: const DemoHome(),
+    );
+  }
+}
+
+class DemoHome extends StatefulWidget {
+  const DemoHome({super.key});
+
+  @override
+  State<DemoHome> createState() => _DemoHomeState();
+}
+
+class _DemoHomeState extends State<DemoHome> {
+  bool selected = false;
+
+  @override
+  Widget build(BuildContext context) {
+    const sizes = IconButtonM3ESize.values;
+    const variants = IconButtonM3EVariant.values;
+
+    return Scaffold(
+      appBar: AppBar(title: const Text('IconButtonM3E Demo')),
+      body: ListView(
+        padding: const EdgeInsets.all(16),
+        children: [
+          Wrap(spacing: 12, runSpacing: 12, children: [
+            Column(
+              children: [
+                const Text('Variants × Sizes (round - width default)',
+                    style:
+                        TextStyle(fontSize: 18, fontWeight: FontWeight.bold)),
+                const SizedBox(height: 8),
+                for (final v in variants) ...[
+                  Text(v.toString().split('.').last.toUpperCase(),
+                      style: const TextStyle(fontWeight: FontWeight.bold)),
+                  const SizedBox(height: 8),
+                  Wrap(
+                    spacing: 12,
+                    runSpacing: 12,
+                    children: [
+                      for (final s in sizes)
+                        IconButtonM3E(
+                          variant: v,
+                          size: s,
+                          width: IconButtonM3EWidth.defaultWidth,
+                          icon: const Icon(Icons.mic),
+                          tooltip: 'Mic',
+                          onPressed: () {},
+                        ),
+                    ],
+                  ),
+                  const SizedBox(height: 16),
+                ],
+              ],
+            ),
+            Column(
+              children: [
+                const Text('Variants × Sizes (round - width narrow)',
+                    style:
+                        TextStyle(fontSize: 18, fontWeight: FontWeight.bold)),
+                const SizedBox(height: 8),
+                for (final v in variants) ...[
+                  Text(v.toString().split('.').last.toUpperCase(),
+                      style: const TextStyle(fontWeight: FontWeight.bold)),
+                  const SizedBox(height: 8),
+                  Wrap(
+                    spacing: 12,
+                    runSpacing: 12,
+                    children: [
+                      for (final s in sizes)
+                        IconButtonM3E(
+                          variant: v,
+                          size: s,
+                          width: IconButtonM3EWidth.narrow,
+                          icon: const Icon(Icons.mic),
+                          tooltip: 'Mic',
+                          onPressed: () {},
+                        ),
+                    ],
+                  ),
+                  const SizedBox(height: 16),
+                ],
+              ],
+            ),
+            Column(
+              children: [
+                const Text('Variants × Sizes (round - width narrow)',
+                    style:
+                        TextStyle(fontSize: 18, fontWeight: FontWeight.bold)),
+                const SizedBox(height: 8),
+                for (final v in variants) ...[
+                  Text(v.toString().split('.').last.toUpperCase(),
+                      style: const TextStyle(fontWeight: FontWeight.bold)),
+                  const SizedBox(height: 8),
+                  Wrap(
+                    spacing: 12,
+                    runSpacing: 12,
+                    children: [
+                      for (final s in sizes)
+                        IconButtonM3E(
+                          variant: v,
+                          size: s,
+                          width: IconButtonM3EWidth.wide,
+                          icon: const Icon(Icons.mic),
+                          tooltip: 'Mic',
+                          onPressed: () {},
+                        ),
+                    ],
+                  ),
+                  const SizedBox(height: 16),
+                ],
+              ],
+            ),
+          ]),
+          const SizedBox(height: 24),
+          const Text('Square shape',
+              style: TextStyle(fontSize: 18, fontWeight: FontWeight.bold)),
+          const SizedBox(height: 8),
+          Wrap(
+            spacing: 12,
+            runSpacing: 12,
+            children: [
+              for (final v in variants)
+                IconButtonM3E(
+                  variant: v,
+                  shape: IconButtonM3EShapeVariant.square,
+                  size: IconButtonM3ESize.md,
+                  icon: const Icon(Icons.share),
+                  tooltip: 'Share',
+                  onPressed: () {},
+                ),
+            ],
+          ),
+          const SizedBox(height: 32),
+          const Text('Toggle example',
+              style: TextStyle(fontSize: 18, fontWeight: FontWeight.bold)),
+          const SizedBox(height: 8),
+          Wrap(
+            spacing: 12,
+            runSpacing: 12,
+            children: [
+              IconButtonM3E(
+                variant: IconButtonM3EVariant.tonal,
+                isSelected: selected,
+                icon: const Icon(Icons.favorite_border),
+                selectedIcon: const Icon(Icons.favorite),
+                tooltip: selected ? 'Unfavorite' : 'Favorite',
+                onPressed: () => setState(() => selected = !selected),
+              ),
+              IconButtonM3E(
+                variant: IconButtonM3EVariant.filled,
+                isSelected: selected,
+                icon: const Icon(Icons.bookmark_add_outlined),
+                selectedIcon: const Icon(Icons.bookmark_added),
+                tooltip: selected ? 'Remove bookmark' : 'Add bookmark',
+                onPressed: () => setState(() => selected = !selected),
+              ),
+            ],
+          ),
+          const SizedBox(height: 32),
+        ],
+      ),
+    );
+  }
+}

packages/icon_button_m3e/example/pubspec.yaml

@@ -0,0 +1,21 @@
+name: icon_button_m3e_example
+description: Example for icon_button_m3e
+publish_to: "none"
+
+environment:
+  sdk: ">=3.2.0 <4.0.0"
+  flutter: ">=3.19.0"
+
+dependencies:
+  flutter:
+    sdk: flutter
+  icon_button_m3e:
+    path: ../
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter
+  flutter_lints: ^4.0.0
+
+flutter:
+  uses-material-design: true

packages/icon_button_m3e/lib/icon_button_m3e.dart

@@ -0,0 +1,4 @@
+library icon_button_m3e;
+
+export 'src/enums.dart';
+export 'src/icon_button_m3e.dart';

packages/icon_button_m3e/lib/src/_tokens_adapter.dart

@@ -0,0 +1,122 @@
+part of 'enums.dart';
+
+/// All numeric tokens & constants for M3 Expressive IconButton.
+/// No business logic here—just data.
+class IconButtonM3ETokens {
+  const IconButtonM3ETokens._();
+
+  // ----------------------------
+  // Icon glyph sizes (dp)
+  // ----------------------------
+  static const Map<IconButtonM3ESize, double> icon = {
+    IconButtonM3ESize.xs: 20.0, // A
+    IconButtonM3ESize.sm: 24.0, // B
+    IconButtonM3ESize.md: 24.0, // C
+    IconButtonM3ESize.lg: 32.0, // D
+    IconButtonM3ESize.xl: 40.0, // E
+  };
+
+  // ----------------------------
+  // Visual container sizes (dp)
+  // width × height
+  // ----------------------------
+  static const Map<IconButtonM3ESize, Map<IconButtonM3EWidth, Size>> visual = {
+    IconButtonM3ESize.xs: {
+      IconButtonM3EWidth.defaultWidth: Size(32, 32),
+      IconButtonM3EWidth.narrow: Size(28, 32),
+      IconButtonM3EWidth.wide: Size(40, 32),
+    },
+    IconButtonM3ESize.sm: {
+      IconButtonM3EWidth.defaultWidth: Size(40, 40),
+      IconButtonM3EWidth.narrow: Size(32, 40),
+      IconButtonM3EWidth.wide: Size(52, 40),
+    },
+    IconButtonM3ESize.md: {
+      IconButtonM3EWidth.defaultWidth: Size(56, 56),
+      IconButtonM3EWidth.narrow: Size(48, 56),
+      IconButtonM3EWidth.wide: Size(72, 56),
+    },
+    IconButtonM3ESize.lg: {
+      IconButtonM3EWidth.defaultWidth: Size(96, 96),
+      IconButtonM3EWidth.narrow: Size(64, 96),
+      IconButtonM3EWidth.wide: Size(128, 96),
+    },
+    IconButtonM3ESize.xl: {
+      IconButtonM3EWidth.defaultWidth: Size(136, 136),
+      IconButtonM3EWidth.narrow: Size(104, 136),
+      IconButtonM3EWidth.wide: Size(184, 136),
+    },
+  };
+
+  // ----------------------------
+  // Minimum interactive target sizes (dp)
+  // XS/SM must be ≥48×48 (SM wide = 52×48); others equal visual.
+  // ----------------------------
+  static const Map<IconButtonM3ESize, Map<IconButtonM3EWidth, Size>> target = {
+    IconButtonM3ESize.xs: {
+      IconButtonM3EWidth.defaultWidth: Size(48, 48),
+      IconButtonM3EWidth.narrow: Size(48, 48),
+      IconButtonM3EWidth.wide: Size(48, 48),
+    },
+    IconButtonM3ESize.sm: {
+      IconButtonM3EWidth.defaultWidth: Size(48, 48),
+      IconButtonM3EWidth.narrow: Size(48, 48),
+      IconButtonM3EWidth.wide: Size(52, 48),
+    },
+    // MD/LG/XL already meet or exceed 48×48 – use visual sizes as targets.
+    IconButtonM3ESize.md: {
+      IconButtonM3EWidth.defaultWidth: Size(56, 56),
+      IconButtonM3EWidth.narrow: Size(48, 56),
+      IconButtonM3EWidth.wide: Size(72, 56),
+    },
+    IconButtonM3ESize.lg: {
+      IconButtonM3EWidth.defaultWidth: Size(96, 96),
+      IconButtonM3EWidth.narrow: Size(64, 96),
+      IconButtonM3EWidth.wide: Size(128, 96),
+    },
+    IconButtonM3ESize.xl: {
+      IconButtonM3EWidth.defaultWidth: Size(136, 136),
+      IconButtonM3EWidth.narrow: Size(104, 136),
+      IconButtonM3EWidth.wide: Size(184, 136),
+    },
+  };
+
+  // ----------------------------
+  // Corner radii (dp)
+  // Pressed radius is shared by both variants at the same size and
+  // is more square than the square resting radius.
+  // Values are consistent, scalable defaults; tune to match your spec.
+  // ----------------------------
+  static const Map<IconButtonM3ESize, double> radiusRestRound = {
+    // Half of the default height → circular/pill look
+    IconButtonM3ESize.xs: 16.0, // 32/2
+    IconButtonM3ESize.sm: 20.0, // 40/2
+    IconButtonM3ESize.md: 28.0, // 56/2
+    IconButtonM3ESize.lg: 48.0, // 96/2
+    IconButtonM3ESize.xl: 68.0, // 136/2
+  };
+
+  static const Map<IconButtonM3ESize, double> radiusRestSquare = {
+    // Rounded-square feel (~25% of height)
+    IconButtonM3ESize.xs: 8.0, // ≈32*0.25
+    IconButtonM3ESize.sm: 10.0, // ≈40*0.25
+    IconButtonM3ESize.md: 14.0, // ≈56*0.25
+    IconButtonM3ESize.lg: 24.0, // ≈96*0.25
+    IconButtonM3ESize.xl: 34.0, // ≈136*0.25
+  };
+
+  static const Map<IconButtonM3ESize, double> radiusPressed = {
+    // More square than the square resting radius (~20% of height)
+    IconButtonM3ESize.xs: 6.0, // ≈32*0.20
+    IconButtonM3ESize.sm: 8.0, // ≈40*0.20
+    IconButtonM3ESize.md: 11.0, // ≈56*0.20
+    IconButtonM3ESize.lg: 19.0, // ≈96*0.20
+    IconButtonM3ESize.xl: 27.0, // ≈136*0.20
+  };
+
+  // ----------------------------
+  // Motion tokens for shape morph (optional, but handy)
+  // ----------------------------
+  static const Duration morphDuration = Duration(milliseconds: 120);
+  static const Curve morphCurve = Curves.easeOut;
+}

packages/icon_button_m3e/lib/src/enums.dart

@@ -0,0 +1,86 @@
+library m3e_iconbutton;
+
+import 'package:flutter/material.dart';
+
+part '_tokens_adapter.dart';
+
+/// Visual scale labels (A–E in the spec).
+enum IconButtonM3ESize { xs, sm, md, lg, xl }
+
+/// Width variants of the button’s container (not the icon glyph).
+enum IconButtonM3EWidth { defaultWidth, narrow, wide }
+
+/// The two resting shape variants.
+enum IconButtonM3EShapeVariant { round, square }
+
+/// Visual variants (kept from previous API).
+enum IconButtonM3EVariant { standard, filled, tonal, outlined }
+
+/// Icon glyph size inside the button (reads tokens).
+extension IconM3EGlyph on IconButtonM3ESize {
+  double get icon => IconButtonM3ETokens.icon[this]!;
+}
+
+/// Visual (painted) size & target size helpers (read tokens).
+extension IconButtonM3ESizes on IconButtonM3ESize {
+  Size visual(IconButtonM3EWidth width) =>
+      IconButtonM3ETokens.visual[this]![width]!;
+
+  Size target(IconButtonM3EWidth width) =>
+      IconButtonM3ETokens.target[this]![width]!;
+
+  Size get defaultSize => visual(IconButtonM3EWidth.defaultWidth);
+  Size get narrowSize => visual(IconButtonM3EWidth.narrow);
+  Size get wideSize => visual(IconButtonM3EWidth.wide);
+}
+
+/// Shape resolution helpers: resting/pressed radii and toggle behavior.
+class IconButtonM3EShapes {
+  const IconButtonM3EShapes._();
+
+  static IconButtonM3EShapeVariant restVariant({
+    required bool isToggle,
+    required bool isSelected,
+    required IconButtonM3EShapeVariant baseVariant,
+  }) {
+    if (isToggle && isSelected) {
+      return baseVariant == IconButtonM3EShapeVariant.round
+          ? IconButtonM3EShapeVariant.square
+          : IconButtonM3EShapeVariant.round;
+    }
+    return baseVariant;
+  }
+
+  static double restingRadius({
+    required IconButtonM3ESize size,
+    required IconButtonM3EShapeVariant variant,
+  }) {
+    return switch (variant) {
+      IconButtonM3EShapeVariant.round =>
+        IconButtonM3ETokens.radiusRestRound[size]!,
+      IconButtonM3EShapeVariant.square =>
+        IconButtonM3ETokens.radiusRestSquare[size]!,
+    };
+  }
+
+  /// Effective corner radius for the given material states.
+  /// Hover does not change the radius; Pressed uses the shared pressed radius.
+  static double effectiveRadius({
+    required IconButtonM3ESize size,
+    required IconButtonM3EShapeVariant baseVariant,
+    required bool isToggle,
+    required bool isSelected,
+    required Set<WidgetState> states,
+  }) {
+    final variant = restVariant(
+      isToggle: isToggle,
+      isSelected: isSelected,
+      baseVariant: baseVariant,
+    );
+
+    if (states.contains(WidgetState.pressed)) {
+      return IconButtonM3ETokens.radiusPressed[size]!;
+    }
+    return restingRadius(size: size, variant: variant);
+  }
+}

packages/icon_button_m3e/lib/src/icon_button_m3e.dart

@@ -0,0 +1,139 @@
+import 'package:flutter/material.dart';
+
+import 'enums.dart';
+
+/// Material 3 Expressive Icon Button
+///
+/// - Visual sizes are defined by [IconButtonM3ETokens.visual] (per size × width)
+/// - Tap target respects [IconButtonM3ETokens.target] with a minimum of 48×48 on XS/SM
+/// - Variants: standard, filled, tonal, outlined
+/// - Shapes: round (pill) or square (rounded rect). Toggle can flip shape when selected.
+/// - Widths: default, narrow, wide
+/// - Toggle: [isSelected] + [selectedIcon]
+class IconButtonM3E extends StatelessWidget {
+  const IconButtonM3E({
+    super.key,
+    required this.icon,
+    this.onPressed,
+    this.tooltip,
+    this.semanticLabel,
+    this.variant = IconButtonM3EVariant.standard,
+    this.size = IconButtonM3ESize.sm,
+    this.shape = IconButtonM3EShapeVariant.round,
+    this.width = IconButtonM3EWidth.defaultWidth,
+    this.isSelected,
+    this.selectedIcon,
+    this.enableFeedback,
+  });
+
+  final Widget icon;
+  final VoidCallback? onPressed;
+  final String? tooltip;
+  final String? semanticLabel;
+  final IconButtonM3EVariant variant;
+  final IconButtonM3ESize size;
+  final IconButtonM3EShapeVariant shape;
+  final IconButtonM3EWidth width;
+  final bool? isSelected;
+  final Widget? selectedIcon;
+  final bool? enableFeedback;
+
+  @override
+  Widget build(BuildContext context) {
+    final scheme = Theme.of(context).colorScheme;
+
+    final Size visual = size.visual(width);
+    final Size target = size.target(width);
+    final double iconPx = size.icon;
+
+    final bool selected = isSelected ?? false;
+    // Consider it a toggle control if selection can be represented.
+    final bool isToggle = isSelected != null || selectedIcon != null;
+
+    // Colors per variant (selected tint for standard).
+    Color bg;
+    Color fg;
+    BorderSide? side;
+    switch (variant) {
+      case IconButtonM3EVariant.standard:
+        bg = Colors.transparent;
+        fg = selected ? scheme.primary : scheme.onSurfaceVariant;
+        side = null;
+        break;
+      case IconButtonM3EVariant.filled:
+        bg = scheme.primary;
+        fg = scheme.onPrimary;
+        side = null;
+        break;
+      case IconButtonM3EVariant.tonal:
+        bg = scheme.secondaryContainer;
+        fg = scheme.onSecondaryContainer;
+        side = null;
+        break;
+      case IconButtonM3EVariant.outlined:
+        bg = Colors.transparent;
+        fg = scheme.primary;
+        side = BorderSide(color: scheme.outline, width: 1);
+        break;
+    }
+
+    // Resolve shape radius based on states (pressed) and toggle/selection.
+    OutlinedBorder shapeFor(Set<WidgetState> states) {
+      final r = IconButtonM3EShapes.effectiveRadius(
+        size: size,
+        baseVariant: shape,
+        isToggle: isToggle,
+        isSelected: selected,
+        states: states,
+      );
+      return RoundedRectangleBorder(borderRadius: BorderRadius.circular(r));
+    }
+
+    final Widget innerIcon = IconTheme.merge(
+      data: IconThemeData(size: iconPx, color: fg),
+      child: (selected && selectedIcon != null) ? selectedIcon! : icon,
+    );
+
+    final Widget button = IconButton(
+      onPressed: onPressed,
+      isSelected: isSelected,
+      selectedIcon: selectedIcon,
+      icon: innerIcon,
+      tooltip: tooltip,
+      enableFeedback: enableFeedback,
+      style: ButtonStyle(
+        // Visual (painted) size
+        fixedSize: WidgetStateProperty.all(visual),
+        padding: WidgetStateProperty.all(EdgeInsets.zero),
+        shape: WidgetStateProperty.resolveWith(shapeFor),
+        backgroundColor: WidgetStateProperty.all(bg),
+        foregroundColor: WidgetStateProperty.resolveWith((_) => fg),
+        side: WidgetStateProperty.resolveWith((_) => side),
+        // Animate pressed shape morph a bit.
+        animationDuration: IconButtonM3ETokens.morphDuration,
+        visualDensity: VisualDensity.standard,
+      ),
+    );
+
+    // Compose into an outer box sized to the minimum interactive target.
+    final Widget core = SizedBox(
+      width: target.width,
+      height: target.height,
+      child: Center(
+        child: SizedBox(
+          width: visual.width,
+          height: visual.height,
+          child: button,
+        ),
+      ),
+    );
+
+    final semanticsText = semanticLabel ?? tooltip;
+    return Semantics(
+      button: true,
+      selected: selected,
+      label: semanticsText,
+      child: core,
+    );
+  }
+}

packages/icon_button_m3e/melos_icon_button_m3e.iml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/example/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/android/.gradle" />
+      <excludeFolder url="file://$MODULE_DIR$/example/android/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/Flutter" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/Pods" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/Flutter" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/Pods" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/.symlinks" />
+    </content>
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="Dart SDK" level="project" />
+    <orderEntry type="library" name="Flutter Plugins" level="project" />
+    <orderEntry type="library" name="Dart Packages" level="project" />
+  </component>
+</module>

packages/icon_button_m3e/pubspec.yaml

@@ -0,0 +1,21 @@
+name: icon_button_m3e
+description: "Material 3 Expressive IconButton with sizes, variants, shapes, toggle, and accessible hit targets."
+version: 0.1.1
+repository: https://github.com/EmilyMonestone/icon_button_m3e
+issue_tracker: https://github.com/EmilyMonestone/icon_button_m3e/issues
+
+environment:
+  sdk: ^3.9.2
+  flutter: ">=1.17.0"
+
+dependencies:
+  flutter:
+    sdk: flutter
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter
+  flutter_lints: ^4.0.0
+
+flutter:
+  uses-material-design: true

packages/icon_button_m3e/pubspec_overrides.yaml

@@ -0,0 +1,4 @@
+# melos_managed_dependency_overrides: m3e_design
+dependency_overrides:
+  m3e_design:
+    path: ..\\m3e_design

packages/icon_button_m3e/test/icon_button_m3e_test.dart

@@ -0,0 +1,46 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:icon_button_m3e/icon_button_m3e.dart';
+
+void main() {
+  testWidgets('Semantics exposes label and selected state', (tester) async {
+    const label = 'Favorite';
+    await tester.pumpWidget(
+      const MaterialApp(
+        home: Material(
+          child: IconButtonM3E(
+            icon: Icon(Icons.favorite_border),
+            selectedIcon: Icon(Icons.favorite),
+            isSelected: true,
+            tooltip: label,
+          ),
+        ),
+      ),
+    );
+
+    final semantics = tester.getSemantics(find.byType(IconButtonM3E));
+    expect(semantics.flagsCollection.hasSelectedState, true);
+    expect(semantics.label, label);
+  });
+
+  testWidgets('Hit target is at least 48x48 when visual is XS (32)', (
+    tester,
+  ) async {
+    await tester.pumpWidget(
+      const MaterialApp(
+        home: Material(
+          child: Center(
+            child: IconButtonM3E(
+              size: IconButtonM3ESize.xs,
+              icon: Icon(Icons.mic),
+            ),
+          ),
+        ),
+      ),
+    );
+
+    final size = tester.getSize(find.byType(IconButtonM3E));
+    expect(size.width, greaterThanOrEqualTo(48));
+    expect(size.height, greaterThanOrEqualTo(48));
+  });
+}

packages/loading_indicator_m3e/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) ...
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

packages/loading_indicator_m3e/README.md

@@ -0,0 +1,56 @@
+# loading_indicator_m3e
+
+Material 3 **Expressive** Loading Indicator for Flutter — a morphing polygon that continuously rotates and morphs between shapes (ported from Android's Material3 `LoadingIndicator`).
+
+Two configurations:
+- **Default** — container uses `secondaryContainer`, active indicator uses `primary`
+- **Contained** — container uses `primaryContainer`, active indicator uses `onPrimaryContainer`
+
+Token-aligned sizes:
+- Container: **48 × 48dp**
+- Active indicator size: **38dp**
+- Container shape: **full** (pill/circular) corners
+
+## Usage
+
+```dart
+import 'package:loading_indicator_m3e/loading_indicator_m3e.dart';
+
+// Default
+const LoadingIndicatorM3E();
+
+// Contained
+const LoadingIndicatorM3E(variant: LoadingIndicatorM3EVariant.contained);
+
+// Custom colors, custom polygon sequence
+LoadingIndicatorM3E(
+  color: Colors.teal,
+  polygons: const [
+    MaterialShapes.sunny,
+    MaterialShapes.cookie9Sided,
+    MaterialShapes.pill,
+  ],
+);
+```
+
+## Notes
+- The inner morph sequence and animation timings match the Compose implementation:
+  - Morph interval ~650ms, global rotation ~4666ms
+  - Active size is scaled to ~38dp inside the 48dp container to avoid clipping while rotating
+- Requires your monorepo `m3e_design` (for tokens) and `material_new_shapes` (for `RoundedPolygon` + `Morph` + `MaterialShapes`). The `pubspec.yaml` is set up with `path: ../...`.
+
+## Monorepo Layout
+
+```
+packages/
+  m3e_design/
+  material_new_shapes/
+  loading_indicator_m3e/
+```
+
+## Accessibility
+Pass `semanticLabel` and `semanticValue` to announce loading status if needed.
+
+## License
+- Android/Compose implementation © Google, Apache-2.0
+- This package MIT

packages/loading_indicator_m3e/lib/loading_indicator_m3e.dart

@@ -0,0 +1,6 @@
+library loading_indicator_m3e;
+
+export 'src/enums.dart';
+export 'src/loading_tokens_adapter.dart' show LoadingTokensAdapter;
+export 'src/expressive_loading_indicator.dart';
+export 'src/loading_indicator_m3e.dart';

packages/loading_indicator_m3e/lib/src/enums.dart

@@ -0,0 +1 @@
+enum LoadingIndicatorM3EVariant { defaultStyle, contained }

packages/loading_indicator_m3e/lib/src/expressive_loading_indicator.dart

@@ -0,0 +1,329 @@
+// Port of Android's LoadingIndicator
+// Source: androidx/compose/material3/material3/src/commonMain/kotlin/androidx/compose/material3/LoadingIndicator.kt
+// Copyright (c) 2024 The Android Open Source Project
+// Licensed under the Apache License, Version 2.0
+
+import 'dart:async';
+import 'dart:math' as math;
+
+import 'package:flutter/material.dart';
+import 'package:flutter/physics.dart';
+import 'package:flutter/semantics.dart';
+import 'package:material_new_shapes/material_new_shapes.dart';
+
+/// A Material Design loading indicator.
+///
+/// This version of the loading indicator morphs between its [polygons] shapes.
+/// ![Loading indicator image](https://developer.android.com/images/reference/androidx/compose/material3/loading-indicator.png)
+class ExpressiveLoadingIndicator extends ProgressIndicator {
+  /// A list of [RoundedPolygon]s for the sequence of shapes this loading indicator
+  /// will morph between. The loading indicator expects at least two items in that list.
+  final List<RoundedPolygon>? polygons;
+
+  /// Defines minimum and maximum sizes for an [ExpressiveLoadingIndicator].
+  /// If null, then the [ProgressIndicatorThemeData.constraints] will be used. Otherwise, defaults to a minimum width and height of 48 pixels.
+  final BoxConstraints? constraints;
+
+  const ExpressiveLoadingIndicator({
+    super.key,
+    super.color,
+    this.polygons,
+    this.constraints,
+    super.semanticsLabel,
+    super.semanticsValue,
+  }) : assert(polygons != null ? polygons.length > 1 : true);
+
+  @override
+  State<ExpressiveLoadingIndicator> createState() =>
+      _ExpressiveLoadingIndicatorState();
+}
+
+class _ExpressiveLoadingIndicatorState extends State<ExpressiveLoadingIndicator>
+    with TickerProviderStateMixin {
+  static final List<RoundedPolygon> _defaultPolygons = [
+    MaterialShapes.softBurst,
+    MaterialShapes.cookie9Sided,
+    MaterialShapes.pentagon,
+    MaterialShapes.pill,
+    MaterialShapes.sunny,
+    MaterialShapes.cookie4Sided,
+    MaterialShapes.oval,
+  ];
+
+  static final BoxConstraints _defaultConstraints = BoxConstraints(
+    minWidth: 48.0,
+    minHeight: 48.0,
+    maxWidth: 48.0,
+    maxHeight: 48.0,
+  ); // default from kotlin source
+
+  late final List<RoundedPolygon> _polygons;
+
+  static const int _globalRotationDurationMs = 4666;
+  static const int _morphIntervalMs = 650;
+  static const double _fullRotation = 360.0;
+
+  static const double _quarterRotation = _fullRotation / 4;
+  static const double _activeSize = 38; // based on source spec
+
+  late final List<Morph> _morphSequence;
+
+  late final AnimationController _morphController;
+  late final AnimationController _globalRotationController;
+  int _currentMorphIndex = 0;
+  double _morphRotationTargetAngle = _quarterRotation;
+
+  Timer? _morphTimer;
+
+  final _morphAnimationSpec = SpringSimulation(
+    SpringDescription.withDampingRatio(ratio: 0.6, stiffness: 200.0, mass: 1.0),
+    0.0,
+    1.0,
+    5.0,
+    snapToEnd: true,
+  );
+
+  late BoxConstraints _constraints;
+  late Color _color;
+
+  @override
+  Widget build(BuildContext context) {
+    final indicatorTheme = ProgressIndicatorTheme.of(context);
+    _color =
+        widget.color ??
+        indicatorTheme.color ??
+        Theme.of(context).colorScheme.primary;
+    _constraints =
+        widget.constraints ?? indicatorTheme.constraints ?? _defaultConstraints;
+
+    final activeIndicatorScale =
+        _activeSize / math.min(_constraints.maxWidth, _constraints.maxHeight);
+
+    final shapesScaleFactor =
+        _calculateScaleFactor(_polygons) * activeIndicatorScale;
+
+    return Semantics.fromProperties(
+      properties: SemanticsProperties(
+        label: widget.semanticsLabel,
+        value: widget.semanticsValue,
+      ),
+      child: RepaintBoundary(
+        child: ConstrainedBox(
+          constraints: _constraints,
+          child: AspectRatio(
+            aspectRatio: 1.0,
+            child: AnimatedBuilder(
+              animation: Listenable.merge([
+                _morphController,
+                _globalRotationController,
+              ]),
+              builder: (context, child) {
+                final morphProgress = _morphController.value.clamp(0.0, 1.0);
+                final globalRotationDegrees =
+                    _globalRotationController.value * _fullRotation;
+
+                // calculate total rotation (clockwise, matching Kotlin implementation)
+                final totalRotationDegrees =
+                    morphProgress * _quarterRotation +
+                    _morphRotationTargetAngle +
+                    globalRotationDegrees;
+
+                final totalRotationRadians =
+                    totalRotationDegrees * (math.pi / 180.0);
+
+                return Transform.rotate(
+                  angle: totalRotationRadians,
+                  child: CustomPaint(
+                    painter: _MorphPainter(
+                      morph: _morphSequence[_currentMorphIndex],
+                      progress: morphProgress,
+                      color: _color,
+                      scaleFactor: shapesScaleFactor,
+                      repaint: Listenable.merge([
+                        _morphController,
+                        _globalRotationController,
+                      ]),
+                    ),
+                    child: const SizedBox.expand(),
+                  ),
+                );
+              },
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+
+  @override
+  void dispose() {
+    _morphTimer?.cancel();
+    _morphController.dispose();
+    _globalRotationController.dispose();
+    super.dispose();
+  }
+
+  @override
+  void initState() {
+    super.initState();
+
+    _polygons = widget.polygons ?? _defaultPolygons;
+
+    _morphSequence = _createMorphSequence(_polygons, circularSequence: true);
+
+    _morphController = AnimationController.unbounded(vsync: this);
+
+    // continuous linear rotation
+    _globalRotationController = AnimationController(
+      duration: const Duration(milliseconds: _globalRotationDurationMs),
+      vsync: this,
+    );
+
+    _startAnimations();
+  }
+
+  List<Morph> _createMorphSequence(
+    List<RoundedPolygon> polygons, {
+    required bool circularSequence,
+  }) {
+    final morphs = <Morph>[];
+
+    for (int i = 0; i < polygons.length; i++) {
+      if (i + 1 < polygons.length) {
+        morphs.add(Morph(polygons[i], polygons[i + 1]));
+      } else if (circularSequence) {
+        // morph from last shape back to first shape
+        morphs.add(Morph(polygons[i], polygons[0]));
+      }
+    }
+
+    return morphs;
+  }
+
+  /// Calculates a scale factor that will be used when scaling the provided [RoundedPolygon]s into a
+  /// specified sized container.
+  ///
+  /// Since the polygons may rotate, a simple [RoundedPolygon.calculateBounds] is not enough to
+  /// determine the size the polygon will occupy as it rotates. Using the simple bounds calculation may
+  /// result in a clipped shape.
+  ///
+  /// This function calculates and returns a scale factor by utilizing the
+  /// [RoundedPolygon.calculateMaxBounds] and comparing its result to the
+  /// [RoundedPolygon.calculateBounds]. The scale factor can later be used when calling [processPath].
+  ///
+  /// Port of Kotlin implementation.
+  double _calculateScaleFactor(List<RoundedPolygon> polygons) {
+    var scaleFactor = 1.0;
+
+    for (final polygon in polygons) {
+      final bounds = polygon.calculateBounds();
+      final maxBounds = polygon.calculateMaxBounds();
+
+      final boundsWidth = bounds[2] - bounds[0];
+      final boundsHeight = bounds[3] - bounds[1];
+
+      final maxBoundsWidth = maxBounds[2] - maxBounds[0];
+      final maxBoundsHeight = maxBounds[3] - maxBounds[1];
+
+      final scaleX = boundsWidth / maxBoundsWidth;
+      final scaleY = boundsHeight / maxBoundsHeight;
+
+      // We use max(scaleX, scaleY) to handle cases like a pill-shape that can throw off the
+      // entire calculation.
+      scaleFactor = math.min(scaleFactor, math.max(scaleX, scaleY));
+    }
+
+    return scaleFactor;
+  }
+
+  void _startAnimations() {
+    // infinite global rotation
+    _globalRotationController.repeat();
+
+    // periodic morph cycle
+    _morphTimer = Timer.periodic(
+      const Duration(milliseconds: _morphIntervalMs),
+      (_) => _startMorphCycle(),
+    );
+
+    _startMorphCycle();
+  }
+
+  void _startMorphCycle() {
+    if (!mounted) return;
+
+    // move to next morph in sequence
+    _currentMorphIndex = (_currentMorphIndex + 1) % _morphSequence.length;
+
+    // accumulate rotation target
+    _morphRotationTargetAngle =
+        (_morphRotationTargetAngle + _quarterRotation) % _fullRotation;
+
+    // Reset and start morph animation
+    _morphController
+      ..value = 0.0
+      ..animateWith(_morphAnimationSpec);
+  }
+}
+
+class _MorphPainter extends CustomPainter {
+  final Morph morph;
+  final double progress;
+  final Color color;
+
+  /// A scale factor that will be taken into account uniformly when the [path] is
+  /// scaled (i.e. the scaleX would be the [size] width x the scale factor, and the scaleY would be
+  /// the [size] height x the scale factor)
+  final double scaleFactor;
+
+  _MorphPainter({
+    required this.morph,
+    required this.progress,
+    required this.color,
+    this.scaleFactor = 1.0,
+    super.repaint,
+  });
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    final path = morph.toPath(progress: progress);
+    final processedPath = _processPath(path, size);
+    canvas.drawPath(
+      processedPath,
+      Paint()
+        ..style = PaintingStyle.fill
+        ..color = color,
+    );
+  }
+
+  @override
+  bool shouldRepaint(_MorphPainter oldDelegate) {
+    return oldDelegate.morph != morph ||
+        oldDelegate.progress != progress ||
+        oldDelegate.color != color ||
+        oldDelegate.scaleFactor != scaleFactor;
+  }
+
+  /// Process a given path to scale it and center it inside the given size.
+  ///
+  /// [path] takes a [Path] that was generated by a _normalized_ [Morph] or [RoundedPolygon].
+  /// [size] takes a [Size] that the provided [path] is going to be scaled and centered into.
+  Path _processPath(Path path, Size size) {
+    // a [Matrix] that would be used to apply the scaling. Note that any provided
+    // matrix will be reset in this function.
+    final Matrix4 scaleMatrix = Matrix4.diagonal3Values(
+      size.width * scaleFactor,
+      size.height * scaleFactor,
+      1,
+    );
+    final Path scaledPath = path.transform(scaleMatrix.storage);
+
+    // Translate the path so that its center aligns with the center of the container.
+    final Rect bounds = scaledPath.getBounds();
+    final Offset translation =
+        Offset(size.width / 2, size.height / 2) - bounds.center;
+    final Path finalPath = scaledPath.shift(translation);
+
+    return finalPath;
+  }
+}

packages/loading_indicator_m3e/lib/src/loading_indicator_m3e.dart

@@ -0,0 +1,83 @@
+import 'package:flutter/material.dart';
+import 'package:material_new_shapes/material_new_shapes.dart';
+import 'expressive_loading_indicator.dart';
+import 'loading_tokens_adapter.dart';
+import 'enums.dart';
+
+/// Material 3 Expressive Loading Indicator
+/// - Default: floating morphing shape on surface
+/// - Contained: icon inside colored container (primary container) using onPrimaryContainer
+class LoadingIndicatorM3E extends StatelessWidget {
+  const LoadingIndicatorM3E({
+    super.key,
+    this.variant = LoadingIndicatorM3EVariant.defaultStyle,
+    this.color,
+    this.containerColor,
+    this.polygons,
+    this.constraints,
+    this.padding,
+    this.semanticLabel,
+    this.semanticValue,
+  });
+
+  final LoadingIndicatorM3EVariant variant;
+  final Color? color;
+  final Color? containerColor;
+  final List<RoundedPolygon>? polygons;
+  final BoxConstraints? constraints;
+  final EdgeInsetsGeometry? padding;
+  final String? semanticLabel;
+  final String? semanticValue;
+
+  @override
+  Widget build(BuildContext context) {
+    final tokens = LoadingTokensAdapter(context);
+    final size = Size(tokens.containerWidth(), tokens.containerHeight());
+
+    final cons = constraints ?? BoxConstraints.tight(size);
+
+    final activeColor = switch (variant) {
+      LoadingIndicatorM3EVariant.defaultStyle => color ?? tokens.activeColor(),
+      LoadingIndicatorM3EVariant.contained => color ?? tokens.containedActiveColor(),
+    };
+
+    final containerBg = switch (variant) {
+      LoadingIndicatorM3EVariant.defaultStyle => containerColor ?? tokens.containerColorDefault(),
+      LoadingIndicatorM3EVariant.contained => containerColor ?? tokens.containedContainerColor(),
+    };
+
+    final indicator = ExpressiveLoadingIndicator(
+      color: activeColor,
+      polygons: polygons,
+      semanticsLabel: semanticLabel,
+      semanticsValue: semanticValue,
+      constraints: cons,
+    );
+
+    if (variant == LoadingIndicatorM3EVariant.defaultStyle) {
+      // Default: subtle container (secondaryContainer)
+      return DecoratedBox(
+        decoration: BoxDecoration(
+          color: containerBg,
+          borderRadius: tokens.containerRadius(),
+        ),
+        child: Padding(
+          padding: padding ?? const EdgeInsets.all(0),
+          child: indicator,
+        ),
+      );
+    }
+
+    // Contained: stronger container (primaryContainer) and contrasting active indicator
+    return DecoratedBox(
+      decoration: BoxDecoration(
+        color: containerBg,
+        borderRadius: tokens.containerRadius(),
+      ),
+      child: Padding(
+        padding: padding ?? const EdgeInsets.all(0),
+        child: indicator,
+      ),
+    );
+  }
+}

packages/loading_indicator_m3e/lib/src/loading_tokens_adapter.dart

@@ -0,0 +1,31 @@
+import 'package:flutter/material.dart';
+import 'package:m3e_design/m3e_design.dart';
+
+@immutable
+class LoadingTokensAdapter {
+  const LoadingTokensAdapter(this.context);
+  final BuildContext context;
+
+  M3ETheme get _m3e {
+    final t = Theme.of(context);
+    return t.extension<M3ETheme>() ?? M3ETheme.defaults(t.colorScheme);
+  }
+
+  // Active indicator color (Default variant)
+  Color activeColor() => _m3e.colors.primary;
+
+  // Container color (Default variant -> transparent background)
+  Color containerColorDefault() => Colors.transparent;
+
+  // Contained variant colors
+  Color containedContainerColor() => _m3e.colors.primaryContainer;
+  Color containedActiveColor() => _m3e.colors.onPrimaryContainer;
+
+  // Size tokens (from spec)
+  double containerWidth() => 48; // container height/width
+  double containerHeight() => 48;
+  double activeIndicatorSize() => 38;
+
+  // Shape: full corners
+  BorderRadius containerRadius() => BorderRadius.circular(999);
+}

packages/loading_indicator_m3e/melos_loading_indicator_m3e.iml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/example/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/android/.gradle" />
+      <excludeFolder url="file://$MODULE_DIR$/example/android/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/Flutter" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/Pods" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/Flutter" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/Pods" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/.symlinks" />
+    </content>
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="Dart SDK" level="project" />
+    <orderEntry type="library" name="Flutter Plugins" level="project" />
+    <orderEntry type="library" name="Dart Packages" level="project" />
+  </component>
+</module>

packages/loading_indicator_m3e/pubspec.yaml

@@ -0,0 +1,19 @@
+name: loading_indicator_m3e
+description: Material 3 Expressive Loading Indicator (morphing polygons) for Flutter, with Default and Contained variants.
+version: 0.1.0
+publish_to: none
+
+environment:
+  sdk: ">=3.5.0 <4.0.0"
+  flutter: ">=3.22.0"
+
+dependencies:
+  flutter:
+    sdk: flutter
+  m3e_design:
+    path: ../m3e_design
+  material_new_shapes: ^1.0.0
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter

packages/loading_indicator_m3e/test/loading_indicator_m3e_test.dart

@@ -0,0 +1,7 @@
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  test('placeholder', () {
+    expect(2 + 2, 4);
+  });
+}

packages/m3e_collection/README.md

@@ -0,0 +1,3 @@
+# m3e_collection
+
+Single import that re-exports all M3E component packages plus `m3e_design`.

packages/m3e_collection/lib/m3e_collection.dart

@@ -0,0 +1,16 @@
+library m3e_collection;
+
+export 'package:app_bar_m3e/app_bar_m3e.dart';
+export 'package:button_group_m3e/button_group_m3e.dart';
+export 'package:button_m3e/button_m3e.dart';
+export 'package:fab_m3e/fab_m3e.dart';
+export 'package:icon_button_m3e/icon_button_m3e.dart';
+export 'package:loading_indicator_m3e/loading_indicator_m3e.dart';
+export 'package:m3e_design/m3e_design.dart';
+export 'package:material_new_shapes/material_new_shapes.dart';
+export 'package:navigation_bar_m3e/navigation_bar_m3e.dart';
+export 'package:navigation_rail_m3e/navigation_rail_m3e.dart';
+export 'package:progress_indicator_m3e/progress_indicator_m3e.dart';
+export 'package:slider_m3e/slider_m3e.dart';
+export 'package:split_button_m3e/split_button_m3e.dart';
+export 'package:toolbar_m3e/toolbar_m3e.dart';

packages/m3e_collection/melos_m3e_collection.iml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/example/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/android/.gradle" />
+      <excludeFolder url="file://$MODULE_DIR$/example/android/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/Flutter" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/Pods" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/Flutter" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/Pods" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/.symlinks" />
+    </content>
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="Dart SDK" level="project" />
+    <orderEntry type="library" name="Flutter Plugins" level="project" />
+    <orderEntry type="library" name="Dart Packages" level="project" />
+  </component>
+</module>

packages/m3e_collection/pubspec.yaml

@@ -0,0 +1,39 @@
+name: m3e_collection
+description: Aggregated exports of all Material 3 Expressive components for Flutter.
+version: 0.1.0
+publish_to: none
+
+environment:
+  sdk: ">=3.5.0 <4.0.0"
+
+dependencies:
+  flutter:
+    sdk: flutter
+  material_new_shapes: ^1.0.0
+  m3e_design:
+    path: ../m3e_design
+  icon_button_m3e:
+    path: ../icon_button_m3e
+  split_button_m3e:
+    path: ../split_button_m3e
+  button_group_m3e:
+    path: ../button_group_m3e
+  app_bar_m3e:
+    path: ../app_bar_m3e
+  button_m3e:
+    path: ../button_m3e
+  fab_m3e:
+    path: ../fab_m3e
+  loading_indicator_m3e:
+    path: ../loading_indicator_m3e
+  progress_indicator_m3e:
+    path: ../progress_indicator_m3e
+  navigation_bar_m3e:
+    path: ../navigation_bar_m3e
+  navigation_rail_m3e:
+    path: ../navigation_rail_m3e
+  slider_m3e:
+    path: ../slider_m3e
+  toolbar_m3e:
+    path: ../toolbar_m3e
+

packages/m3e_collection/pubspec_overrides.yaml

@@ -0,0 +1,29 @@
+# melos_managed_dependency_overrides: icon_button_m3e,m3e_design,split_button_m3e,app_bar_m3e,button_m3e,fab_m3e,loading_indicator_m3e,progress_indicator_m3e,navigation_bar_m3e,navigation_rail_m3e,slider_m3e,toolbar_m3e,button_group_m3e
+dependency_overrides:
+  icon_button_m3e:
+    path: ..\\icon_button_m3e
+  m3e_design:
+    path: ..\\m3e_design
+  split_button_m3e:
+    path: ..\\split_button_m3e
+  app_bar_m3e:
+    path: ..\\app_bar_m3e
+  button_m3e:
+    path: ..\\button_m3e
+  fab_m3e:
+    path: ..\\fab_m3e
+  loading_indicator_m3e:
+    path: ..\\loading_indicator_m3e
+  progress_indicator_m3e:
+    path: ..\\progress_indicator_m3e
+  navigation_bar_m3e:
+    path: ..\\navigation_bar_m3e
+  navigation_rail_m3e:
+    path: ..\\navigation_rail_m3e
+  slider_m3e:
+    path: ..\\slider_m3e
+  toolbar_m3e:
+    path: ..\\toolbar_m3e
+  button_group_m3e:
+    path: ..\\button_group_m3e
+

packages/m3e_design/README.md

@@ -0,0 +1,4 @@
+# m3e_design
+
+Design language core for Material 3 Expressive (Flutter).
+Provides ThemeExtension and token accessors for color, typography, shapes, spacing, motion.

packages/m3e_design/lib/m3e_design.dart

@@ -0,0 +1,10 @@
+library m3e_design;
+
+export 'theme/m3e_theme.dart';
+export 'tokens/color_tokens.dart';
+export 'tokens/motion_tokens.dart';
+export 'tokens/shape_tokens.dart';
+export 'tokens/spacing_tokens.dart';
+export 'tokens/typography_tokens.dart';
+export 'utils/build_context_x.dart';
+export 'utils/semantics_x.dart';

packages/m3e_design/lib/theme/m3e_theme.dart

@@ -0,0 +1,99 @@
+import 'package:flutter/material.dart';
+
+import '../tokens/color_tokens.dart';
+import '../tokens/motion_tokens.dart';
+import '../tokens/shape_tokens.dart';
+import '../tokens/spacing_tokens.dart';
+import '../tokens/typography_tokens.dart';
+
+@immutable
+class M3ETheme extends ThemeExtension<M3ETheme> {
+  final M3EColors colors;
+  final M3ETypography typography;
+  final M3EShapes shapes;
+  final M3ESpacing spacing;
+  final M3EMotion motion;
+
+  const M3ETheme({
+    required this.colors,
+    required this.typography,
+    required this.shapes,
+    required this.spacing,
+    required this.motion,
+  });
+
+  // Convenience proxy for commonly used text styles in packages (m3e.type.*)
+  _M3ETypeProxy get type => _M3ETypeProxy(typography);
+
+  static M3ETheme defaults(ColorScheme scheme) => M3ETheme(
+        colors: M3EColors.from(scheme),
+        typography: M3ETypography.defaultFor(scheme.brightness),
+        shapes: M3EShapes.expressive(),
+        spacing: const M3ESpacing.regular(),
+        motion: const M3EMotion.expressive(),
+      );
+
+  @override
+  M3ETheme copyWith({
+    M3EColors? colors,
+    M3ETypography? typography,
+    M3EShapes? shapes,
+    M3ESpacing? spacing,
+    M3EMotion? motion,
+  }) =>
+      M3ETheme(
+        colors: colors ?? this.colors,
+        typography: typography ?? this.typography,
+        shapes: shapes ?? this.shapes,
+        spacing: spacing ?? this.spacing,
+        motion: motion ?? this.motion,
+      );
+
+  @override
+  M3ETheme lerp(covariant M3ETheme? other, double t) {
+    if (other == null) return this;
+    return M3ETheme(
+      colors: M3EColors.lerp(colors, other.colors, t),
+      typography: M3ETypography.lerp(typography, other.typography, t),
+      shapes: M3EShapes.lerp(shapes, other.shapes, t),
+      spacing: M3ESpacing.lerp(spacing, other.spacing, t),
+      motion: M3EMotion.lerp(motion, other.motion, t),
+    );
+  }
+}
+
+/// Inject (or replace) the M3ETheme extension on a ThemeData.
+ThemeData withM3ETheme(ThemeData base, {M3ETheme? override}) {
+  // Use any existing M3ETheme, else the provided override, else defaults.
+  final current = base.extension<M3ETheme>();
+  final next = override ?? current ?? M3ETheme.defaults(base.colorScheme);
+
+  // Merge existing extensions (values) with our M3ETheme, replacing prior ones.
+  final Iterable<ThemeExtension<dynamic>> existing = base.extensions.values;
+  final List<ThemeExtension<dynamic>> merged = <ThemeExtension<dynamic>>[];
+  for (final e in existing) {
+    if (e is! M3ETheme) {
+      merged.add(e);
+    }
+  }
+  merged.add(next);
+
+  return base.copyWith(extensions: merged);
+}
+
+// Internal proxy for typography shortcuts used by components.
+class _M3ETypeProxy {
+  const _M3ETypeProxy(this._t);
+  final M3ETypography _t;
+
+  TextStyle get _empty => const TextStyle();
+  TextStyle get titleLarge => _t.base.titleLarge ?? _empty;
+  TextStyle get titleSmall => _t.base.titleSmall ?? _empty;
+  TextStyle get bodySmall => _t.base.bodySmall ?? _empty;
+  TextStyle get labelLarge => _t.base.labelLarge ?? _empty;
+  TextStyle get labelMedium => _t.base.labelMedium ?? _empty;
+  TextStyle get labelSmall => _t.base.labelSmall ?? _empty;
+
+  TextStyle get headlineSmallEmphasized =>
+      (_t.base.headlineSmall ?? _empty).merge(_t.emphasized.headline);
+}

packages/m3e_design/lib/tokens/color_tokens.dart

@@ -0,0 +1,196 @@
+import 'package:flutter/material.dart';
+
+@immutable
+class M3EColors {
+  final Color emphasis;
+  final Color onEmphasis;
+  final Color info;
+  final Color success;
+  final Color warning;
+  final Color danger;
+
+  final Color surfaceStrong;
+  final Color onSurfaceStrong;
+  final Color outlineStrong;
+
+  // New: proxy common ColorScheme fields used across packages
+  final Color primary;
+  final Color onPrimary;
+  final Color primaryContainer;
+  final Color onPrimaryContainer;
+
+  final Color secondary;
+  final Color onSecondary;
+  final Color secondaryContainer;
+  final Color onSecondaryContainer;
+
+  final Color tertiary;
+  final Color onTertiary;
+  final Color tertiaryContainer;
+  final Color onTertiaryContainer;
+
+  final Color surface;
+  final Color onSurface;
+  final Color onSurfaceVariant;
+
+  final Color error;
+  final Color onError;
+  final Color errorContainer;
+  final Color onErrorContainer;
+
+  final Color outline;
+  final Color outlineVariant;
+
+  // New: container surface tokens not always present on older ColorScheme
+  final Color surfaceContainerHigh;
+  final Color surfaceContainerLowest;
+
+  const M3EColors({
+    required this.emphasis,
+    required this.onEmphasis,
+    required this.info,
+    required this.success,
+    required this.warning,
+    required this.danger,
+    required this.surfaceStrong,
+    required this.onSurfaceStrong,
+    required this.outlineStrong,
+    // New fields
+    required this.primary,
+    required this.onPrimary,
+    required this.primaryContainer,
+    required this.onPrimaryContainer,
+    required this.secondary,
+    required this.onSecondary,
+    required this.secondaryContainer,
+    required this.onSecondaryContainer,
+    required this.tertiary,
+    required this.onTertiary,
+    required this.tertiaryContainer,
+    required this.onTertiaryContainer,
+    required this.surface,
+    required this.onSurface,
+    required this.onSurfaceVariant,
+    required this.error,
+    required this.onError,
+    required this.errorContainer,
+    required this.onErrorContainer,
+    required this.outline,
+    required this.outlineVariant,
+    required this.surfaceContainerHigh,
+    required this.surfaceContainerLowest,
+  });
+
+  factory M3EColors.from(ColorScheme s) {
+    // Compute container surface variants if not available on the ColorScheme version in use.
+    // We prefer mild blends that work in both light/dark.
+    Color computeSurfaceContainerHigh() =>
+        Color.alphaBlend(s.primary.withValues(alpha: 0.12), s.surface);
+    Color computeSurfaceContainerLowest() =>
+        Color.alphaBlend(s.onSurface.withValues(alpha: 0.05), s.surface);
+
+    return M3EColors(
+      emphasis: s.primary,
+      onEmphasis: s.onPrimary,
+      info: s.tertiary,
+      success: Color.alphaBlend(
+          Colors.green.shade400.withValues(alpha: 0.2), s.primaryContainer),
+      warning: Color.alphaBlend(
+          Colors.orange.shade400.withValues(alpha: 0.2), s.secondaryContainer),
+      danger: Color.alphaBlend(
+          Colors.red.shade400.withValues(alpha: 0.2), s.errorContainer),
+      surfaceStrong:
+          Color.alphaBlend(s.primary.withValues(alpha: 0.06), s.surface),
+      onSurfaceStrong: s.onSurface,
+      outlineStrong:
+          Color.alphaBlend(s.primary.withValues(alpha: 0.40), s.outlineVariant),
+      // New fields mapped from ColorScheme
+      primary: s.primary,
+      onPrimary: s.onPrimary,
+      primaryContainer: s.primaryContainer,
+      onPrimaryContainer: s.onPrimaryContainer,
+      secondary: s.secondary,
+      onSecondary: s.onSecondary,
+      secondaryContainer: s.secondaryContainer,
+      onSecondaryContainer: s.onSecondaryContainer,
+      tertiary: s.tertiary,
+      onTertiary: s.onTertiary,
+      tertiaryContainer: s.tertiaryContainer,
+      onTertiaryContainer: s.onTertiaryContainer,
+      surface: s.surface,
+      onSurface: s.onSurface,
+      onSurfaceVariant: s.onSurfaceVariant,
+      error: s.error,
+      onError: s.onError,
+      errorContainer: s.errorContainer,
+      onErrorContainer: s.onErrorContainer,
+      outline: s.outline,
+      outlineVariant: s.outlineVariant,
+      surfaceContainerHigh: (() {
+        // If the ColorScheme already has a matching field, prefer that via dynamic access; otherwise compute.
+        try {
+          final dynamic dyn = s;
+          final c = dyn.surfaceContainerHigh as Color?;
+          return c ?? computeSurfaceContainerHigh();
+        } catch (_) {
+          return computeSurfaceContainerHigh();
+        }
+      })(),
+      surfaceContainerLowest: (() {
+        try {
+          final dynamic dyn = s;
+          final c = dyn.surfaceContainerLowest as Color?;
+          return c ?? computeSurfaceContainerLowest();
+        } catch (_) {
+          return computeSurfaceContainerLowest();
+        }
+      })(),
+    );
+  }
+
+  static M3EColors lerp(M3EColors a, M3EColors b, double t) => M3EColors(
+        emphasis: Color.lerp(a.emphasis, b.emphasis, t)!,
+        onEmphasis: Color.lerp(a.onEmphasis, b.onEmphasis, t)!,
+        info: Color.lerp(a.info, b.info, t)!,
+        success: Color.lerp(a.success, b.success, t)!,
+        warning: Color.lerp(a.warning, b.warning, t)!,
+        danger: Color.lerp(a.danger, b.danger, t)!,
+        surfaceStrong: Color.lerp(a.surfaceStrong, b.surfaceStrong, t)!,
+        onSurfaceStrong: Color.lerp(a.onSurfaceStrong, b.onSurfaceStrong, t)!,
+        outlineStrong: Color.lerp(a.outlineStrong, b.outlineStrong, t)!,
+        // New fields
+        primary: Color.lerp(a.primary, b.primary, t)!,
+        onPrimary: Color.lerp(a.onPrimary, b.onPrimary, t)!,
+        primaryContainer:
+            Color.lerp(a.primaryContainer, b.primaryContainer, t)!,
+        onPrimaryContainer:
+            Color.lerp(a.onPrimaryContainer, b.onPrimaryContainer, t)!,
+        secondary: Color.lerp(a.secondary, b.secondary, t)!,
+        onSecondary: Color.lerp(a.onSecondary, b.onSecondary, t)!,
+        secondaryContainer:
+            Color.lerp(a.secondaryContainer, b.secondaryContainer, t)!,
+        onSecondaryContainer:
+            Color.lerp(a.onSecondaryContainer, b.onSecondaryContainer, t)!,
+        tertiary: Color.lerp(a.tertiary, b.tertiary, t)!,
+        onTertiary: Color.lerp(a.onTertiary, b.onTertiary, t)!,
+        tertiaryContainer:
+            Color.lerp(a.tertiaryContainer, b.tertiaryContainer, t)!,
+        onTertiaryContainer:
+            Color.lerp(a.onTertiaryContainer, b.onTertiaryContainer, t)!,
+        surface: Color.lerp(a.surface, b.surface, t)!,
+        onSurface: Color.lerp(a.onSurface, b.onSurface, t)!,
+        onSurfaceVariant:
+            Color.lerp(a.onSurfaceVariant, b.onSurfaceVariant, t)!,
+        error: Color.lerp(a.error, b.error, t)!,
+        onError: Color.lerp(a.onError, b.onError, t)!,
+        errorContainer: Color.lerp(a.errorContainer, b.errorContainer, t)!,
+        onErrorContainer:
+            Color.lerp(a.onErrorContainer, b.onErrorContainer, t)!,
+        outline: Color.lerp(a.outline, b.outline, t)!,
+        outlineVariant: Color.lerp(a.outlineVariant, b.outlineVariant, t)!,
+        surfaceContainerHigh:
+            Color.lerp(a.surfaceContainerHigh, b.surfaceContainerHigh, t)!,
+        surfaceContainerLowest:
+            Color.lerp(a.surfaceContainerLowest, b.surfaceContainerLowest, t)!,
+      );
+}

packages/m3e_design/lib/tokens/motion_tokens.dart

@@ -0,0 +1,43 @@
+import 'package:flutter/material.dart';
+
+@immutable
+class M3EMotion {
+  final SpringDescription spatialFast;
+  final SpringDescription spatialMedium;
+  final SpringDescription spatialGentle;
+
+  final SpringDescription effectsFast;
+  final SpringDescription effectsMedium;
+
+  final Duration fast;
+  final Duration medium;
+  final Duration slow;
+
+  const M3EMotion({
+    required this.spatialFast,
+    required this.spatialMedium,
+    required this.spatialGentle,
+    required this.effectsFast,
+    required this.effectsMedium,
+    required this.fast,
+    required this.medium,
+    required this.slow,
+  });
+
+  const M3EMotion.expressive()
+      : spatialFast = const SpringDescription(mass: 1, stiffness: 500, damping: 30),
+        spatialMedium = const SpringDescription(mass: 1, stiffness: 350, damping: 28),
+        spatialGentle = const SpringDescription(mass: 1, stiffness: 220, damping: 24),
+        effectsFast = const SpringDescription(mass: 1, stiffness: 420, damping: 32),
+        effectsMedium = const SpringDescription(mass: 1, stiffness: 280, damping: 28),
+        fast = const Duration(milliseconds: 150),
+        medium = const Duration(milliseconds: 250),
+        slow = const Duration(milliseconds: 400);
+
+  static M3EMotion lerp(M3EMotion a, M3EMotion b, double t) => a;
+}
+
+class SpringDescription {
+  final double mass, stiffness, damping;
+  const SpringDescription({required this.mass, required this.stiffness, required this.damping});
+}

packages/m3e_design/lib/tokens/shape_tokens.dart

@@ -0,0 +1,51 @@
+import 'package:flutter/material.dart';
+
+enum M3EShapeVariant { round, square }
+
+@immutable
+class M3EShapeSet {
+  final BorderRadius xs;
+  final BorderRadius sm;
+  final BorderRadius md;
+  final BorderRadius lg;
+  final BorderRadius xl;
+  const M3EShapeSet({required this.xs, required this.sm, required this.md, required this.lg, required this.xl});
+}
+
+@immutable
+class M3EShapes {
+  final M3EShapeSet round;
+  final M3EShapeSet square;
+
+  const M3EShapes({required this.round, required this.square});
+
+  factory M3EShapes.expressive() => const M3EShapes(
+        round: M3EShapeSet(
+          xs: BorderRadius.all(Radius.circular(999)),
+          sm: BorderRadius.all(Radius.circular(20)),
+          md: BorderRadius.all(Radius.circular(28)),
+          lg: BorderRadius.all(Radius.circular(44)),
+          xl: BorderRadius.all(Radius.circular(64)),
+        ),
+        square: M3EShapeSet(
+          xs: BorderRadius.all(Radius.circular(6)),
+          sm: BorderRadius.all(Radius.circular(8)),
+          md: BorderRadius.all(Radius.circular(12)),
+          lg: BorderRadius.all(Radius.circular(16)),
+          xl: BorderRadius.all(Radius.circular(20)),
+        ),
+      );
+
+  static M3EShapes lerp(M3EShapes a, M3EShapes b, double t) => M3EShapes(
+    round: _lerpSet(a.round, b.round, t),
+    square: _lerpSet(a.square, b.square, t),
+  );
+
+  static M3EShapeSet _lerpSet(M3EShapeSet a, M3EShapeSet b, double t) => M3EShapeSet(
+    xs: BorderRadius.lerp(a.xs, b.xs, t)!,
+    sm: BorderRadius.lerp(a.sm, b.sm, t)!,
+    md: BorderRadius.lerp(a.md, b.md, t)!,
+    lg: BorderRadius.lerp(a.lg, b.lg, t)!,
+    xl: BorderRadius.lerp(a.xl, b.xl, t)!,
+  );
+}

packages/m3e_design/lib/tokens/spacing_tokens.dart

@@ -0,0 +1,37 @@
+import 'package:flutter/material.dart';
+
+@immutable
+class M3ESpacing {
+  final double xs; // 4
+  final double sm; // 8
+  final double md; // 12
+  final double lg; // 16
+  final double xl; // 24
+  final double xxl; // 32
+
+  const M3ESpacing({
+    required this.xs,
+    required this.sm,
+    required this.md,
+    required this.lg,
+    required this.xl,
+    required this.xxl,
+  });
+
+  const M3ESpacing.regular()
+      : xs = 4,
+        sm = 8,
+        md = 12,
+        lg = 16,
+        xl = 24,
+        xxl = 32;
+
+  static M3ESpacing lerp(M3ESpacing a, M3ESpacing b, double t) => M3ESpacing(
+        xs: a.xs + (b.xs - a.xs) * t,
+        sm: a.sm + (b.sm - a.sm) * t,
+        md: a.md + (b.md - a.md) * t,
+        lg: a.lg + (b.lg - a.lg) * t,
+        xl: a.xl + (b.xl - a.xl) * t,
+        xxl: a.xxl + (b.xxl - a.xxl) * t,
+      );
+}

packages/m3e_design/lib/tokens/typography_tokens.dart

@@ -0,0 +1,54 @@
+import 'package:flutter/material.dart';
+
+@immutable
+class M3EEmphasized {
+  final TextStyle display;
+  final TextStyle headline;
+  final TextStyle title;
+  final TextStyle label;
+
+  const M3EEmphasized({
+    required this.display,
+    required this.headline,
+    required this.title,
+    required this.label,
+  });
+
+  static M3EEmphasized forBrightness(Brightness b) {
+    return const M3EEmphasized(
+      display: TextStyle(fontWeight: FontWeight.w800, letterSpacing: -0.5),
+      headline: TextStyle(fontWeight: FontWeight.w700, letterSpacing: -0.25),
+      title: TextStyle(fontWeight: FontWeight.w700),
+      label: TextStyle(fontWeight: FontWeight.w700),
+    );
+  }
+
+  static M3EEmphasized lerp(M3EEmphasized a, M3EEmphasized b, double t) =>
+      M3EEmphasized(
+        display: TextStyle.lerp(a.display, b.display, t)!,
+        headline: TextStyle.lerp(a.headline, b.headline, t)!,
+        title: TextStyle.lerp(a.title, b.title, t)!,
+        label: TextStyle.lerp(a.label, b.label, t)!,
+      );
+}
+
+@immutable
+class M3ETypography {
+  final TextTheme base;
+  final M3EEmphasized emphasized;
+
+  const M3ETypography({required this.base, required this.emphasized});
+
+  factory M3ETypography.defaultFor(Brightness b) {
+    // Use a minimal baseline; app's ThemeData will provide fuller TextTheme.
+    const textTheme = TextTheme();
+    return M3ETypography(
+        base: textTheme, emphasized: M3EEmphasized.forBrightness(b));
+  }
+
+  static M3ETypography lerp(M3ETypography a, M3ETypography b, double t) =>
+      M3ETypography(
+        base: TextTheme.lerp(a.base, b.base, t),
+        emphasized: M3EEmphasized.lerp(a.emphasized, b.emphasized, t),
+      );
+}

packages/m3e_design/lib/utils/build_context_x.dart

@@ -0,0 +1,7 @@
+import 'package:flutter/material.dart';
+import '../theme/m3e_theme.dart';
+
+extension BuildContextM3EX on BuildContext {
+  M3ETheme get m3e =>
+      Theme.of(this).extension<M3ETheme>() ?? M3ETheme.defaults(Theme.of(this).colorScheme);
+}

packages/m3e_design/lib/utils/semantics_x.dart

@@ -0,0 +1,5 @@
+import 'package:flutter/material.dart';
+
+extension SemanticsX on Widget {
+  Widget withLabel(String label) => Semantics(label: label, child: this);
+}

packages/m3e_design/melos_m3e_design.iml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/example/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/example/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/android/.gradle" />
+      <excludeFolder url="file://$MODULE_DIR$/example/android/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/Flutter" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/Pods" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/Flutter" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/Pods" />
+      <excludeFolder url="file://$MODULE_DIR$/example/macos/.symlinks" />
+    </content>
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="Dart SDK" level="project" />
+    <orderEntry type="library" name="Flutter Plugins" level="project" />
+    <orderEntry type="library" name="Dart Packages" level="project" />
+  </component>
+</module>

packages/m3e_design/pubspec.yaml

@@ -0,0 +1,16 @@
+name: m3e_design
+description: Material 3 Expressive design language for Flutter (tokens, ThemeExtension, motion).
+version: 0.1.0
+publish_to: none
+repository: https://example.com/your-repo
+
+environment:
+  sdk: ">=3.5.0 <4.0.0"
+
+dependencies:
+  flutter:
+    sdk: flutter
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter

packages/navigation_bar_m3e/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) ...
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.