How to add opacity a container in flutter? Fade a container?

 

import 'package:flutter/material.dart';

void main(List<String> args) {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});
  @
override

  Widget build(BuildContext context) {
    return const MaterialApp(
      home: Scaffold(
        body: MyLayoutWidget(),
      ),
    );
  }
}

class MyLayoutWidget extends StatelessWidget {
  const MyLayoutWidget({
    super.key,
  });
  @
override

  Widget build(BuildContext context) {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.spaceEvenly,
        children: [
          Opacity(
            opacity: 0.5,
            child: Container(
              height: 200,
              width: 200,
              color: Colors.blue,
              child: const Center(child: Text("With Opacity")),
            ),
          ),
          Container(
            height: 200,
            width: 200,
            color: Colors.blue,
            child: const Center(child: Text("Without Opacity")),
          )
        ],
      ),
    );
  }
}