import 'package:flutter/material.dart';

void main() {
  runApp(const MainApp());
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(
        inputDecorationTheme: const InputDecorationTheme(
          isCollapsed: true, // This doesn't work
          border: OutlineInputBorder(
            borderRadius: BorderRadius.all(Radius.circular(4)),
          ),
        ),
      ),
      home: const Scaffold(
        body: Center(
          child: SizedBox(
            width: 200,
            child: TextField(
              decoration: InputDecoration(
                // isCollapsed: true, // <-- This works
                hintText: 'Hello, Flutter!',
              ),
            ),
          ),
        ),
      ),
    );
  }
}