vant-weapp/packages/slider/index.less

@import '../common/style/var.less';
@import '../common/style/theme.less';

.van-slider {
  position: relative;
  .theme(height, '@slider-bar-height');
  .theme(border-radius, '@border-radius-max');
  .theme(background-color, '@slider-inactive-background-color');

  // use pseudo element to expand click area
  &::before {
    position: absolute;
    right: 0;
    left: 0;
    content: '';
    .theme(top, '-@padding-xs');
    .theme(bottom, '-@padding-xs');
  }

  &__bar {
    position: relative;
    width: 100%;
    height: 100%;
    .theme(background-color, '@slider-active-background-color');

    border-radius: inherit;
    .theme(transition, 'all @animation-duration-fast');
  }

  &__button {
    .theme(width, '@slider-button-width');
    .theme(height, '@slider-button-height');
    .theme(border-radius, '@slider-button-border-radius');
    .theme(box-shadow, '@slider-button-box-shadow');
    .theme(background-color, '@slider-button-background-color');

    &-wrapper {
      position: absolute;
      top: 50%;
      right: 0;
      transform: translate3d(50%, -50%, 0);
    }
  }

  &--disabled {
    .theme(opacity, '@slider-disabled-opacity');
  }
}