.loading {
  background-color: black;
  opacity: 0.2;
  position: absolute;
  width: 100%;
  height: 100%;
  top: 0px;
  left: 0px;
}

.circle{
  width:100px;
  height:100px;
  border-radius:150px;
  border:15px solid #fff;
  border-top-color:rgba(0,0,0,0.3);
  box-sizing:border-box;
  position:absolute;
  top:45%;
  left:45%;
  animation:circle 1s linear infinite;
  -webkit-animation:circle 1s linear infinite;
}
@keyframes circle{
  0%{transform:rotate(0deg)}
  100%{transform:rotate(360deg)}
}
@-webkit-keyframes circle{
  0%{-webkit-transform:rotate(0deg)}
  100%{-webkit-transform:rotate(360deg)}
}