How to clip the corners of Positioned widget in flutter

Here is the output which I am getting:

I want to clip the green Positioned widget on corners with that of grey Container's rounded corners. Any Help will be highly appreciated.

My current code:

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: CustomCard(
          title: 'Custom Card', percentage: 50.0, color: Colors.green),
    );
  }
}

class CustomCard extends StatelessWidget {
  final String title;
  final double percentage;
  final Color color;
  CustomCard(
      {required this.title, required this.percentage, required this.color});
  @override
  Widget build(BuildContext context) {
    double width = MediaQuery.of(context).size.width;
    return Scaffold(
      appBar: AppBar(
        title: Text(title),
      ),
      body: Padding(
        padding: const EdgeInsets.all(8.0),
        child: Stack(clipBehavior: Clip.antiAliasWithSaveLayer, children: [
          Container(
            height: 100.0,
            width: width,
            decoration: BoxDecoration(
              borderRadius: BorderRadius.circular(10),
              color: Colors.grey,
            ),
          ),
          Positioned(
            left: -(percentage / 100) * width,
            top: -(percentage / 100) * width,
            child: Container(
              height: (percentage / 100) * width * 2,
              width: (percentage / 100) * width * 2,
              decoration: BoxDecoration(
                borderRadius:
                    BorderRadius.circular(((percentage / 100) * width)),
                color: color,
              ),
            ),
          ),
        ]),
      ),
    );
  }
}

Thank You.

@Ketan if you wrap the Stack with `ClipRRect1 widget and provide it a border radius then it will add border to both green and gray area.

class CustomCard extends StatelessWidget {
  final String title;
  final double percentage;
  final Color color;
  CustomCard({this.title, this.percentage, this.color});
  @override
  Widget build(BuildContext context) {
    double width = MediaQuery.of(context).size.width;
    return Scaffold(
      appBar: AppBar(
        title: Text(title),
      ),
      body: Padding(
          padding: const EdgeInsets.all(8.0),
          child: ClipRRect(
            borderRadius: BorderRadius.circular(10),
            child: Stack(clipBehavior: Clip.antiAliasWithSaveLayer, children: [
              Container(
                height: 100.0,
                width: width,
                decoration: BoxDecoration(
                  borderRadius: BorderRadius.circular(10),
                  color: Colors.grey,
                ),
              ),
              Positioned(
                left: -(percentage / 100) * width,
                top: -(percentage / 100) * width,
                child: Container(
                  height: (percentage / 100) * width * 2,
                  width: (percentage / 100) * width * 2,
                  decoration: BoxDecoration(
                    borderRadius:
                        BorderRadius.circular(((percentage / 100) * width)),
                    color: color,
                  ),
                ),
              ),
            ]),
          )),
    );
  }
}