#loader {
  position: fixed;
  top: 50%;
  left: 50%;
  width: 40px;
  height: 40px;
  margin: -20px;
  border: 10px solid #ccc;
  border-top-color: #2196f3;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  z-index: 9999;
}
@keyframes spin {
  to { transform: rotate(360deg); }
}