body {
}

.loader {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  display: inline-block;
  border-top: 4px solid #0000FF;
  border-right: 4px solid transparent;
  box-sizing: border-box;
  animation: rotation 1s linear infinite;
}

.loader::after {
  content: '';  
  box-sizing: border-box;
  position: absolute;
  left: 0;
  top: 0;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border-left: 4px solid #FF3D00;
  border-bottom: 4px solid transparent;
  animation: rotation 0.5s linear infinite reverse;
}

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

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