#loading-wrapper {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgb(255, 255, 255);  /* 初始为白色 */
    z-index: 199999;
    transition: all 0.8s ease;
}

.loader, .loader:before, .loader:after {
  border-radius: 50%;
  width: 2.5em;
  height: 2.5em;
  animation-fill-mode: both;
  animation: bblFadInOut 1.8s infinite ease-in-out;
}
.loader {
  color: #FFF;
  font-size: 7px;
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  text-indent: -9999em;
  transform: translateZ(0);
  animation-delay: -0.16s;
}
.loader:before,
.loader:after {
  content: '';
  position: absolute;
  top: 0;
}
.loader:before {
  left: -3.5em;
  animation-delay: -0.32s;
}
.loader:after {
  left: 3.5em;
}

@keyframes bblFadInOut {
  0%, 80%, 100% { box-shadow: 0 2.5em 0 -1.3em }
  40% { box-shadow: 0 2.5em 0 0 }
}