Can you provide the code for a Flutter login screen using a Firebase backend?
To create a Flutter login screen using a Firebase backend, you can use the following code:

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

class LoginPage extends StatefulWidget {
  @override
  _LoginPageState createState() => _LoginPageState();
}

class _LoginPageState extends State<LoginPage> {
  final _auth = FirebaseAuth.instance;
  String email;
  String password;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        padding: EdgeInsets.all(20),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            TextField(
              decoration: InputDecoration(hintText: 'Email'),
              onChanged: (value) {
                email = value;
              },
            ),
            SizedBox(
              height: 20,
            ),
            TextField(
              decoration: InputDecoration(hintText: 'Password'),
              onChanged: (value) {
                password = value;
              },
            ),
            SizedBox(
              height: 20,
            ),
            RaisedButton(
              child: Text('Login'),
              onPressed: () async {
                try {
                  final user = await _auth.signInWithEmailAndPassword(
                      email: email, password: password);
                  if (user != null) {
                    Navigator.pushNamed(context, '/home');
                  }
                } catch (e) {
                  print(e);
                }
              },
            )
          ],
        ),
      ),
    );
  }
}