/* Spinner Animation */
@keyframes spinner {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

.spinner {
  margin: 50px auto;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: 4px solid #f3f3f3;
  border-top: 4px solid #3498db;
  animation: spinner 2s linear infinite;
}