Cant fill in color in expanded container - Flutter

Question

I am a beginner in Flutter, why is there no response after I add color to the expanded Container? But there hasn't been an error. All I want to achieve is to fill the entire area with a score with the red color. What is the problem here?

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

class HomePage extends StatefulWidget {
  const HomePage({Key? key}) : super(key: key);

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body:Column(
        children: [
          Container(
            padding: const EdgeInsets.only(top:50,left:20),
            child: Row(
              children: [
                Icon(Icons.menu,size:30,color:Colors.black54),
                Expanded(child: Container(
                  color: Colors.red,
                )),
                Container(
                  margin: const EdgeInsets.only(right:20),
                  width: 50,
                  height: 50,
                  decoration: BoxDecoration(
                    borderRadius: BorderRadius.circular(10),
                      color: Colors.grey.withOpacity(0.5),
                  ),
                )
              ],
            ),
          )
        ],
      ),
    );
  }
}

Answer 1

You need to include height on Container

Expanded(
  child: Container(
    color: Colors.red,
    height: 50, // same as other children
  ),
),