.loader {
  border: 5px solid rgba(255, 255, 255, 0.3);
  border-radius: 50%;
  border-top: 5px solid #00bcd4;
  width: 50px;
  height: 50px;
  animation: spin 1s linear infinite;
  position: fixed;
  top: 50%;
  left: 50%;
  margin-top: -25px;
  margin-left: -25px;
  z-index: 9999;
  background: rgba(0, 0, 0, 0.5);
  box-shadow: 0 0 20px rgba(0, 188, 212, 0.5);
}

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