body {
  background-color: #f8f9fa;
}
.login-container {
  max-width: 400px;
  margin: 80px auto;
  padding: 30px;
  background: white;
  border-radius: 8px;
  box-shadow: 0 0 10px rgba(0,0,0,0.1);
}

.btn:active {
  transform: scale(0.98);
}