.loader {
  border: 16px solid #f3f3f3;
  border-radius: 50%;
  border-top: 16px solid #3498db;
  width: 120px;
  height: 120px;
  -webkit-animation: spin 0.75s linear infinite; /* Safari */
  animation: spin 0.75s linear infinite;

  margin: 0;
  position: absolute;
  top: calc(50% - 60px);
  left: calc(50% - 60px);
  -ms-transform: translate(-50%, -50%);
  transform: translate(-50%, -50%);
}

/* Safari */
@-webkit-keyframes spin {
  0% { -webkit-transform: rotate(0deg); }
  100% { -webkit-transform: rotate(360deg); }
}

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