#dart

Design Flutter apps with platform-adaptive UI. Architecture: 1. StatelessWidget and StatefulWidget patterns. 2. Provider or Riverpod for state management. 3. Platform checks for iOS/Android differences. 4. Cupertino widgets for iOS feel. 5. Material Design 3 for Android. 6. Responsive layouts with LayoutBuilder. 7. Custom theming with ThemeData. 8. Navigation with GoRouter. Use const constructors for performance and implement accessibility with Semantics.