.loader.shadowExpandX {
  width: 16px;
  height: 16px;
  border-radius: 50%;
  display: block;
  margin:15px auto;
  position: relative;
  background: #FFF;
  box-sizing: border-box;
  animation: shadowExpandX 2s linear infinite alternate;
}
@keyframes shadowExpandX {
  0% {
    box-shadow: 0 0, 0 0;
    color: rgba(255, 255, 255, 0.2);
  }
  100% {
    box-shadow: -24px 0, 24px 0;
    color: rgba(255, 255, 255, 0.8);
  }
}