/* HTML: <div class="loader"></div> */
#loading {
  width: 120px;
  height: 20px;
  background: 
    linear-gradient(90deg,#0001 33%,#0005 50%,#0001 66%)
    #f2f2f2;
  background-size:300% 100%;
  animation: l1 1s infinite linear;
}
@keyframes l1 {
  0% {background-position: right}
}