Flutter - Stack with listview

main.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.light().copyWith(
          scaffoldBackgroundColor: Colors.grey.shade100,
          primaryColor: Colors.amber,
        ),
        debugShowCheckedModeBanner: false,
        home: MyWidget());
  }
}

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Hello world"),
        elevation: 0,
        backgroundColor: Theme.of(context).primaryColor,
      ),
      body: Stack(
        fit: StackFit.loose,
        children: [
        Container(color: Theme.of(context).primaryColor, height: 150),
        Align(
          alignment: Alignment.topLeft,
          heightFactor: 1,
          child: ListView(
            shrinkWrap: false,
            padding: const EdgeInsets.all(16.0),
            children: [
              Row(children: [
                Expanded(
                  child: Container(
                      padding: const EdgeInsets.only(right: 8),
                      color: Colors.white,
                      height: 30),
                ),
                Icon(Icons.search)
              ]),
              const SizedBox(
                height: 16,
              ),
              Card(
                elevation: 8,
                child: Container(
                    color: Colors.white,
                    child: Text("Add calendar here"),
                    height: 200),
              ),
              const SizedBox(
                height: 16,
              ),
              Card(
                elevation: 8,
                child: Container(
                    color: Colors.white,
                    child: Text("Today Section"),
                    height: 100),
              ),
              const SizedBox(
                height: 16,
              ),
              Card(
                elevation: 8,
                child: Container(
                    color: Colors.white,
                    child: Text("Tomorrow Section"),
                    height: 100),
              ),
              const SizedBox(
                height: 16,
              ),
              Card(
                elevation: 8,
                child: Container(
                    color: Colors.white,
                    child: Text("Any other Section"),
                    height: 100),
              ),
            ],
          ),
        )
      ]),
    );
  }
}