
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Login</title>
  <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css">
  <style>
    body {
      background-color: #212529;
      color: #fff;
      display: flex;
      justify-content: center;
      align-items: center;
      height: 100vh;
    }
    .login-form {
      width: 300px;
      background-color: #343a40;
      padding: 20px;
      border-radius: 5px;
      box-shadow: 0 2px 5px rgba(0, 0, 0, 0.3);
      color: #fff;
    }
    label {
      color: #fff;
    }
  </style>
</head>
<body>
  <div class="login-form">
    <form>
      <div class="form-group">
        <label for="username">Email</label>
        <input type="email" class="form-control" id="username" placeholder="Enter your email">
      </div>
      <div class="form-group">
        <label for="password">Password</label>
        <input type="password" class="form-control" id="password" placeholder="Enter your password">
      </div>
      <button type="submit" class="btn btn-primary btn-block">Sign in</button>
    </form>
    <div id="error-message" class="text-danger mt-2"></div>
  </div>
  <script>
    const form = document.querySelector('form');
    form.addEventListener('submit', (event) => {
      event.preventDefault();
      const errorMessage = document.getElementById('error-message');
      errorMessage.textContent = 'Invalid username or password.';
    });
  </script>
</body>
</html>