რა არის Material და Cupertino widgets?

// Material widgets follow Google's Material Design (Android look, but usable anywhere)
MaterialApp(                       // the app root for Material apps
  home: Scaffold(                  // Material page structure
    appBar: AppBar(title: Text('Material')),
    body: Center(
      child: ElevatedButton(       // Material button
        onPressed: () {},
        child: Text('Material Button'),
      ),
    ),
    floatingActionButton: FloatingActionButton(onPressed: () {}),
  ),
)
// Material widgets: Scaffold, AppBar, ElevatedButton, Card, FloatingActionButton, etc.