Синяя полоска в конце экрана трепещет

Я создаю панель инструментов из флаттера. в моем коде я использовал однодетский прокрутки, и он не работает. и я получаю Синяя линия в конце страницы перед нижней панелью навигации. Я думаю, это потому, что страница не прокручивается. В консоли не отображается ошибка. как мне это исправить? оцените вашу помощь в этом.

import 'package:flutter/material.dart';

    import '../constants/colors.dart';
    import '../widgets/bottomNavigation.dart';
    
    class DashboardScreen extends StatefulWidget {
      const DashboardScreen({Key? key}) : super(key: key);
    
      @override
      _DashboardScreenState createState() => _DashboardScreenState();
    }
    
    class _DashboardScreenState extends State<DashboardScreen> {
      @override
      Widget build(BuildContext context) {
        return Scaffold(
          appBar: AppBar(
            actions: [
              Padding(
                padding: const EdgeInsets.only(right: 15),
                child: Container(
                  width: 30,
                  child: Image.asset(
                    'assets/images/user.png',
                  ),
                ),
              ),
            ],
            backgroundColor: Colors.transparent,
            elevation: 0.0,
            iconTheme: IconThemeData(color: Colors.black),
          ),
          drawer: Drawer(),
          body: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Padding(
                padding: const EdgeInsets.only(top: 20, left: 20),
                child: Text(
                  "Hi, NEO",
                  style: TextStyle(
                    fontSize: 25,
                    color: Colors.black,
                    fontWeight: FontWeight.bold,
                    //fontFamily: "Dubai"
                  ),
                ),
              ),
              SizedBox(
                height: 30,
              ),
              Row(
                mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                children: [
                  Container(
                    height: 100,
                    width: 100,
                    decoration: BoxDecoration(
                      borderRadius: BorderRadius.circular(10),
                      color: Colors.green,
                    ),
                  ),
                  Container(
                    height: 100,
                    width: 100,
                    decoration: BoxDecoration(
                      borderRadius: BorderRadius.circular(10),
                      color: Colors.deepPurple,
                    ),
                  ),
                  Container(
                    height: 100,
                    width: 100,
                    decoration: BoxDecoration(
                      borderRadius: BorderRadius.circular(10),
                      color: Colors.blue,
                    ),
                  ),
                ],
              ),
              // SizedBox(
              //   height: 30,
              // ),
    
              Row(
                children: [
                  Padding(
                    padding: const EdgeInsets.only(top: 30, left: 20),
                    child: Text(
                      "Your Leads",
                      style: TextStyle(
                        fontSize: 20,
                        color: Colors.black,
                        fontWeight: FontWeight.bold,
                        //fontFamily: "Dubai"
                      ),
                    ),
                  ),
                ],
              ),
              SizedBox(
                height:30 ,
              ),
    
              Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
    
                  Container(
                    height: 75,
                    width: 350,
                    decoration: BoxDecoration(
                     // borderRadius: BorderRadius.circular(10),
                      color: Colors.white,
                      boxShadow: [
                        BoxShadow(
                          offset: Offset(0, 1),
                          blurRadius: 5,
                          color: Colors.black.withOpacity(0.3),
                        ),
                      ],
                    ),
                  )
                ],
              ),
              Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
    
                  Container(
                    height: 75,
                    width: 350,
                    decoration: BoxDecoration(
                     // borderRadius: BorderRadius.circular(10),
                      color: Colors.white,
                      boxShadow: [
                        BoxShadow(
                          offset: Offset(0, 1),
                          blurRadius: 5,
                          color: Colors.black.withOpacity(0.3),
                        ),
                      ],
                    ),
                  )
                ],
              ),
              SizedBox(
                height: 20,
              ),
    
              Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
    
                  Container(
                    height: 75,
                    width: 350,
                    decoration: BoxDecoration(
                      // borderRadius: BorderRadius.circular(10),
                      color: Colors.lightGreen,
                      boxShadow: [
                        BoxShadow(
                          offset: Offset(0, 1),
                          blurRadius: 5,
                          color: Colors.black.withOpacity(0.3),
                        ),
                      ],
                    ),
                  )
                ],
              ),
              SizedBox(
                height: 20,
              ),
              Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
    
                  Container(
                    height: 75,
                    width: 350,
                    decoration: BoxDecoration(
                      // borderRadius: BorderRadius.circular(10),
                      color: Colors.white,
                      boxShadow: [
                        BoxShadow(
                          offset: Offset(0, 1),
                          blurRadius: 5,
                          color: Colors.black.withOpacity(0.3),
                        ),
                      ],
                    ),
                  )
                ],
              ),
              Expanded(child: Container(child: BottomNavigation())),
            ],
          ),
        );
      }
    }
[![][1]][1]

//нижняя навигация

импортировать 'пакет: флаттер/material.dart';

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

  @override
  State<BottomNavigation> createState() => _BottomNavigationState();
}

class _BottomNavigationState extends State<BottomNavigation> {
  int _selectedIndex = 0;
  static const TextStyle optionStyle =
  TextStyle(fontSize: 30, fontWeight: FontWeight.bold);
  static const List<Widget> _widgetOptions = <Widget>[
    Text(
      'Index 0: Home',
      style: optionStyle,
    ),
    Text(
      'Index 1: Business',
      style: optionStyle,
    ),
    Text(
      'Index 2: School',
      style: optionStyle,
    ),
  ];

  void _onItemTapped(int index) {
    setState(() {
      _selectedIndex = index;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('BottomNavigationBar Sample'),
      ),
      body: Center(
        child: _widgetOptions.elementAt(_selectedIndex),
      ),
      bottomNavigationBar: BottomNavigationBar(
        items: const <BottomNavigationBarItem>[
          BottomNavigationBarItem(
            icon: Icon(Icons.home),
            label: 'Home',
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.business),
            label: 'Business',
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.school),
            label: 'School',
          ),
        ],
        currentIndex: _selectedIndex,
        selectedItemColor: Colors.amber[800],
        onTap: _onItemTapped,
      ),
    );
  }
}