antd-mobile/cjs/components/mask/mask.css

<div align="center">

.adm-mask {
  --z-index: var(--adm-mask-z-index, 1000);
  position: fixed;
  top: 0;
  left: 0;
  z-index: var(--z-index);
  display: block;
  width: 100%;
  height: 100%;
}
.adm-mask-aria-button {
  position: absolute;
  top: 0;
  left: 0;
  z-index: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}
.adm-mask-content {
  z-index: 1;
}