.loading {
  list-style: none;
  margin: 0;
  padding: 0;
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 0;
  z-index: 2100;
}
.loading li {
  height: 0;
  position: absolute;
  top: 50%;
  left: 0;
  width: 0;
  margin: 0;
  height: 50px;
  width: 50px;
  border: 3px solid #337ab7;
  border-radius: 100%;
  transform: transformZ(0);
  animation: LOADING 2s infinite;
}
.loading li:nth-child(1n) {
  left: -50px;
  animation-delay: 0s;
}
.loading li:nth-child(2n) {
  left: 0;
  animation-delay: 0.2s;
}
.loading li:nth-child(3n) {
  left: 50px;
  animation-delay: 0.4s;
}

@keyframes LOADING {
  0% {
    transform: scale(0.5);
    background: #337ab7;
  }
  50% {
    transform: scale(1);
    background: white;
  }
  100% {
    transform: scale(0.5);
    background: #337ab7;
  }
}