.loader {
 --clr: #3498db;
 /* color of spining  */
 width: 50px;
 height: 50px;
 position: relative;
}

.loader:before, .loader:after {
 content: "";
 position: absolute;
 top: -10px;
 left: -10px;
 width: 100%;
 height: 100%;
 border-radius: 100%;
 border: 10px solid transparent;
 border-top-color: var(--clr);
}

.loader:before {
 z-index: 100;
 animation: spin 1s infinite;
}

.loader:after {
 border: 10px solid #ccc;
}

@keyframes spin {
 0% {
  -webkit-transform: rotate(0deg);
  -ms-transform: rotate(0deg);
  -o-transform: rotate(0deg);
  transform: rotate(0deg);
 }

 100% {
  -webkit-transform: rotate(360deg);
  -ms-transform: rotate(360deg);
  -o-transform: rotate(360deg);
  transform: rotate(360deg);
 }
}