SO question: https://stackoverflow.com/q/71134564/10976714

container_full_width_SO.dart

// for SO question: https://stackoverflow.com/q/71134564/10976714
// ignore_for_file: avoid_function_literals_in_foreach_calls, avoid_print

import 'package:flutter/material.dart';

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

class ContainerWidthExampleApp extends StatelessWidget {
  const ContainerWidthExampleApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(title),
      ),
      body: const Center(child: ContainerWidget()),
    );
  }
}

class ContainerWidget extends StatelessWidget {
  const ContainerWidget({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Container(
      color: Colors.red,
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          const Text(
            'You have pushed the button this many times:',
          ),
          SizedBox(
            child: Container(
              color: Colors.blue,
              child: const Center( // <~~~ or `Align`
                child: Text(
                  'You have pushed the',
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }
}