.spinner {
  width: 50px;
  height: 50px;
  border: 6px solid #ddd;
  border-top-color: #3498db;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin: 50px auto;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}