如何在Flutter中突出显示特定字母的文本？

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Highlight Text Example'),
        ),
        body: Center(
          child: RichText(
            text: TextSpan(
              text: 'Hello Flutter',
              style: DefaultTextStyle.of(context).style,
              children: <TextSpan>[
                TextSpan(
                  text: 'F',
                  style: TextStyle(
                    fontWeight: FontWeight.bold,
                    color: Colors.red,
                  ),
                ),
                TextSpan(
                  text: 'lutter',
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }
}