Cannot use dark theme

[chitoadinugraha]

I tried setting

theme: ThemeData(brightness: Brightness.dark), on the materialApp, it's not working.

I also tried using evalpad with this code::

import 'package:flutter/material.dart';

Widget main() {
  return MyApp();
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'flutter_eval demo',
      theme: ThemeData(brightness: Brightness.dark),
      darkTheme: ThemeData(brightness: Brightness.dark),
      themeMode: ThemeMode.dark,
      home: const MyHomePage(title: 'flutter_eval demo home page dark'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key, required this.title}) : super(key: key);

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  _MyHomePageState();
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          crossAxisAlignment: CrossAxisAlignment.center,
          children: <Widget>[
            const Text(
              'You have pushed the button this many times',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        )
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}

But it still using light theme.