MaterialApp(
  theme: ThemeData(
    primarySwatch: Colors.green,
    textTheme: TextTheme(
      bodyMedium: TextStyle(fontSize: 16, color: Colors.black87),
    ),
  ),
  home: MyHomePage(),
)

Text("ยินดีต้อนรับ", style: Theme.of(context).textTheme.bodyMedium)

ElevatedButton(
  onPressed: () {},
  child: Text("กดฉัน")
)

MaterialApp(
  theme: ThemeData.light(),
  darkTheme: ThemeData.dark(),
  themeMode: ThemeMode.system, // เปิด dark mode ตามระบบเครื่อง
  home: MyApp(),
)

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(
        primarySwatch: Colors.deepPurple,
        textTheme: TextTheme(
          bodyMedium: TextStyle(fontSize: 18, color: Colors.deepPurple[900]),
        ),
        elevatedButtonTheme: ElevatedButtonThemeData(
          style: ElevatedButton.styleFrom(backgroundColor: Colors.deepPurple),
        ),
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text("ธีมและการตกแต่ง")),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text("สวัสดี Flutter!", style: Theme.of(context).textTheme.bodyMedium),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: () {},
              child: Text("ปุ่มสวย ๆ"),
            )
          ],
        ),
      ),
    );
  }
}