anchor.diff:    }
   }
   
  -class StartupPage extends StatelessWidget {
  -  final Widget _logo = SvgPicture.asset('assets/images/logo.svg',
  -      semanticsLabel: 'Polaris logo');
  +class LoginForm extends StatefulWidget {
  +  @override
  +  _LoginFormState createState() => _LoginFormState();
  +}
   
  -  Widget get _loginForm {
  +class _LoginFormState extends State<LoginForm> {
  +  final _usernameEditingController = TextEditingController();
  +  final _passwordEditingController = TextEditingController();
  +
  +  @override
  +  Widget build(BuildContext context) {
       return Form(
         child: Column(
           children: [
             TextFormField(
  +            controller: _usernameEditingController,
               decoration: const InputDecoration(
                 icon: Icon(Icons.person),
                 labelText: "Username",
               ),
             ),
             TextFormField(
  +            controller: _passwordEditingController,
  +            obscureText: true,
  +            enableSuggestions: false,
  +            autocorrect: false,
               decoration: const InputDecoration(
                 icon: Icon(Icons.lock),
                 labelText: "Password",
  
positive.code:       );
      }));
    }
  
    onLoginPressed() {}
  }
  
negative.code:           Padding(
                padding: EdgeInsets.only(top: 24),
                child: ElevatedButton(
                    onPressed: _onLoginPressed, child: Text("LOGIN")))
          ],
        ),
      );
    }
  
    _onLoginPressed() async {}
  
    @override
    void dispose() {
      _usernameEditingController.dispose();
      super.dispose();
    }
  }
  
  class StartupPage extends StatelessWidget {
    final Widget _logo = SvgPicture.asset('assets/images/logo.svg',
        semanticsLabel: 'Polaris logo');
  
    @override
    Widget build(BuildContext context) {
  