.loader {
  border: 4px solid #f3f3f3;
  border-radius: 50%;
  border-top: 4px solid #3498db;
  width: 15px;
  height: 15px;
  -webkit-animation: spin 2s linear infinite; /* Safari */
  animation: spin 2s linear infinite;
}


@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}