message: style: --van-border-color should affect hairline
diff: pointer-events: none;
  }
  -.hairline(@color: @border-color) {
  +.hairline(@color: var(--van-border-color)) {
  .hairline-common();
  top: -50%;
  transform: scale(0.5);
  }
  -.hairline-top(@color: @border-color, @left: 0, @right: 0) {
  +.hairline-top(@color: var(--van-border-color), @left: 0, @right: 0) {
  .hairline-common();
  top: 0;
  transform: scaleY(0.5);
  }
  -.hairline-bottom(@color: @border-color, @left: 0, @right: 0) {
  +.hairline-bottom(@color: var(--van-border-color), @left: 0, @right: 0) {
  .hairline-common();
  right: @right;
  