SOURCE

<div class="loading">
    <div class="bg">
      <div class="ico"></div>
    </div>
</div>

.loading {
  display: flex;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  justify-content: center;
  align-items: center;
  z-index: 9999;
}
 .bg {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100px;
    height: 100px;
    background: rgba(0, 0, 0, .4);
    border-radius: 10px;
  }
.ico {
      border: 10px solid #f3f3f3;
      border-radius: 50%;
      border-top: 10px solid #00a4b8;
      width: 60px;
      height: 60px;
      -webkit-animation: spin 2s linear infinite;
      animation: spin 2s linear infinite;
    }

 @-webkit-keyframes spin {
      0% { -webkit-transform: rotate(0deg); }
      100% { -webkit-transform: rotate(360deg); }
    }
    @keyframes spin {
      0% { transform: rotate(0deg); }
      100% { transform: rotate(360deg); }
    }