.loading-bg{
  display: flex;
  width: 100%;
  height: 100%;
  position: fixed;
  background-image: url();
  background-color:(246,240,246); /*可以此处改为你需要的背景色，日间模式，，或者在自定义引入的custom.css进行覆盖，custom.css是什么请看 魔改配置 章节*/
  z-index: 1001;
  opacity: 1;
  transition: 0.3s;
}

.loading-img {
  background: url(https://avatars.githubusercontent.com/u/149315495?s=400&u=35789284796e584dbaaac1634d60d423dde4b39e&v=4) no-repeat center center;
  background-size: cover;
}