vant/packages/vant-css/src/mixins/border_retina.css

@import '../common/var.css';

$border-poses: top, right, bottom, left;

@define-mixin border-retina $poses: $border-poses, $border-retina-color: $gray-light {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 200%;
  height: 200%;
  transform: scale(.5);
  transform-origin: 0 0;
  pointer-events: none;
  box-sizing: border-box;

  @each $pos in $poses {
    border-$(pos): 1px solid $border-retina-color;
  }
}

@define-mixin hairline $border-retina-color: $gray-light {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 200%;
  height: 200%;
  transform: scale(.5);
  transform-origin: 0 0;
  pointer-events: none;
  box-sizing: border-box;
  border: 0 solid $border-retina-color;
}