add border to progressbar around its content

progressbar_border.dart

import 'package:flutter/material.dart';

const Color darkBlue = Color.fromARGB(255, 18, 32, 47);

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.dark().copyWith(
        scaffoldBackgroundColor: darkBlue,
      ),
      debugShowCheckedModeBanner: false,
      home: MyHome(),
    );
  }
}

class MyHome extends StatelessWidget {
  List<Widget> get contentWidgets => [
        Container(
          height: 40,
          width: 180,
          color: Colors.green,
          child: const FittedBox(
            child: Text(
              '60%',
              textAlign: TextAlign.center,
              style: TextStyle(
                color: Colors.white,
              ),
            ),
          ),
        ),
        Container(
          height: 40,
          width: 90,
          color: Colors.blue,
          child: const FittedBox(
            child: Text(
              '30%',
              textAlign: TextAlign.center,
              style: TextStyle(
                color: Colors.white,
              ),
            ),
          ),
        ),
        Container(
          height: 40,
          width: 30,
          color: Colors.red,
          child: const FittedBox(
            child: Text(
              '10%',
              textAlign: TextAlign.center,
              style: TextStyle(
                color: Colors.white,
              ),
            ),
          ),
        ),
      ];

  double get borderWidth => 2;
  double get radius => 8;
  BorderRadius get borderRadius => BorderRadius.circular(radius);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: DecoratedBox(
          decoration: BoxDecoration(
            borderRadius: borderRadius,
            color: Colors.amber,
          ),
          child: Padding(
            padding: EdgeInsets.all(borderWidth),
            child: ClipRRect(
              borderRadius: borderRadius,
              child: Row(
                mainAxisSize: MainAxisSize.min,
                children: contentWidgets,
              ),
            ),
          ),
        ),
      ),
    );
  }
}