Footer does not stay fixed at the bottom

[kpTops]

When the list of options is short, the footer widget (in this case, the SIGN IN button) does not remain at the bottom of the screen. Instead, it shifts upward along with the content.

How can I make the footer stay fixed at the bottom of the screen, regardless of the list length?

I’ve attached a screenshot for reference.

void main() {
  ClassBuilder.registerClasses();
  runApp(MyApp());
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(primarySwatch: Colors.blue),
      home: MainWidget(),
    );
  }
}

class MainWidget extends StatefulWidget {
  const MainWidget({super.key});

  @override
  State<MainWidget> createState() => _MainWidgetState();
}

class _MainWidgetState extends State<MainWidget> with TickerProviderStateMixin {
  late KFDrawerController _drawerController;

  @override
  void initState() {
    super.initState();
    _drawerController = KFDrawerController(
      initialPage: ClassBuilder.fromString('MainPage'),
      items: [
        KFDrawerItem.initWithPage(
          text: Text('MAIN', style: TextStyle(color: Colors.white)),
          icon: Icon(Icons.home, color: Colors.white),
          page: MainPage(),
        ),
        KFDrawerItem.initWithPage(
          text: Text('CALENDAR', style: TextStyle(color: Colors.white)),
          icon: Icon(Icons.calendar_today, color: Colors.white),
          page: CalendarPage(),
        ),
        KFDrawerItem.initWithPage(
          text: Text('SETTINGS', style: TextStyle(color: Colors.white)),
          icon: Icon(Icons.settings, color: Colors.white),
          page: ClassBuilder.fromString('SettingsPage'),
        ),
      ],
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: KFDrawer(
        //        borderRadius: 0.0,
        //        shadowBorderRadius: 0.0,
        //        menuPadding: EdgeInsets.all(0.0),
        //        scrollable: true,
        controller: _drawerController,
        animationDuration: Duration(milliseconds: 280),
        slideCurve: Curves.easeInOutCubic,
        scaleCurve: Curves.easeInOutBack,
        header: Align(
          alignment: Alignment.centerLeft,
          child: Container(
            padding: EdgeInsets.symmetric(horizontal: 16.0),
            width: MediaQuery.of(context).size.width * 0.6,
            child: Image.asset(
              'assets/logo.png',
              alignment: Alignment.centerLeft,
            ),
          ),
        ),
        footer: KFDrawerItem(
          text: Text('SIGN IN', style: TextStyle(color: Colors.white)),
          icon: Icon(Icons.input, color: Colors.white),
          onPressed: () {
            Navigator.of(context).push(
              CupertinoPageRoute(
                fullscreenDialog: true,
                builder: (BuildContext context) {
                  return AuthPage();
                },
              ),
            );
          },
        ),
        decoration: BoxDecoration(
          gradient: LinearGradient(
            begin: Alignment.topLeft,
            end: Alignment.bottomRight,
            colors: [
              Color.fromRGBO(255, 255, 255, 1.0),
              Color.fromRGBO(44, 72, 171, 1.0),
            ],
            tileMode: TileMode.repeated,
          ),
        ),
      ),
    );
  }
}