$bg: #c9c9c9;
$blue: #525e7a;

html {
  background: $bg;
}

.loader {
  width: 19.0rem;
  height: 19.0rem;
  margin: 50px auto;
  position: relative;
  background: $blue;
  border-radius: 50%;
  animation: loading 0.5s linear infinite;
  
  &:after {
    content: '';
    position: absolute;
    width: 18.5rem;
    height: 18.5rem;
    top: 1px; 
    right: 0;
    left: 0;
    margin: auto;
    background: $bg;
    border-radius: 50%;
  }
}

@keyframes loading {
  to {
    transform: rotate(360deg);
  }
}