Typography

main.dart

import 'package:flutter/material.dart';

void main() => runApp(
      MaterialApp(
        theme: ThemeData(
          fontFamily: 'Roboto',
          useMaterial3: true,
          textTheme: const TextTheme(
            bodyMedium: TextStyle(
              color: Colors.red,
              fontSize: 30,
              fontWeight: FontWeight.bold,
            ),
            bodySmall: TextStyle(
              color: Colors.purple,
              fontSize: 10,
            ),
          ),
        ),
        debugShowCheckedModeBanner: false,
        home: Builder(
          builder: (context) => Scaffold(
            body: Center(
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  const Text('Default Text Style'),
                  Text('Body Small',
                      style: Theme.of(context).textTheme.bodySmall),
                ],
              ),
            ),
          ),
        ),
      ),
    );