#loader {
  background-color: palevioletred;
  width: 50px;
  height: 50px;
  margin: auto auto;
  position: fixed;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  animation: spin 2s linear infinite;
  border-radius: 50%;
  border: 5px solid #000;
  border-top: 5px solid #3498db;
}

@media (max-width: 800px) {
  #loader {
    left: 40%;
  }
}

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