antd-mobile/cjs/components/center-popup/center-popup.css

<div align="center">

.adm-center-popup {
  --background-color: var(--adm-center-popup-background-color, var(--adm-color-background));
  --border-radius: var(--adm-center-popup-border-radius, 8px);
  --max-width: var(--adm-center-popup-max-width, 75vw);
  --min-width: var(--adm-center-popup-min-width, 280px);
  --z-index: var(--adm-center-popup-z-index, 1000);
  position: fixed;
  z-index: var(--z-index);
}
.adm-center-popup .adm-center-popup-mask {
  z-index: 0;
}
.adm-center-popup-wrap {
  position: fixed;
  z-index: 1;
  top: 50%;
  left: 50%;
  width: auto;
  min-width: var(--min-width);
  max-width: var(--max-width);
  transform: translate(-50%, -50%);
}
.adm-center-popup-body {
  background-color: var(--background-color);
  border-radius: var(--border-radius);
}
.adm-center-popup-close {
  position: absolute;
  z-index: 100;
  right: 8px;
  top: 8px;
  cursor: pointer;
  padding: 4px;
  font-size: 18px;
  color: var(--adm-color-weak);
}