mini-ar-demo/miniprogram/pages/myth/myth.wxss

/* pages/dunhuang/dunhuang.wxss */
.page {
  position: relative;
}
.loading {
  width: 100vw;
  height: 100vh;
  position: absolute;
  top: 0;
  left: 0;
  z-index: 1000;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  background: #ffffff;
  background-image: url('https://houseoss.4dkankan.com/mini-ar-test/assets/bg.png');
  background-position: center top;
  background-size: cover;
  background-repeat: no-repeat;
}