ant-design/style/components/slider.less

@sliderClass: ~"@{css-prefix}slider";

// slider color
@disabledColor: #ccc;
// tooltip
@tooltip-color: #fff;
@tooltip-bg: tint(#666, 4%);
@tooltip-arrow-width: 4px;
@tooltip-distance: @tooltip-arrow-width+4;
@tooltip-arrow-color: @tooltip-bg;

.@{sliderClass} {
  position: relative;
  margin: 12px 0;
  height: 4px;
  width: 100%;
  border-radius: @border-radius-base;
  background-color: #e9e9e9;

  &-track {
    position: absolute;
    left: 0;
    height: 4px;
    border-radius: @border-radius-base;
    background-color: tint(@primary-color, 60%);
    z-index: 1;
  }

  &-handle {
    position: absolute;
    margin-left: -7px;
    margin-top: -5px;
    width: 14px;
    height: 14px;
    cursor: pointer;
    border-radius: 50%;
    border: solid 2px tint(@primary-color, 50%);
    background-color: #fff;
    z-index: 2;

    &:hover {
      border-color: tint(@primary-color, 20%);
    }
    &-active {
      &:active {
        border-color: tint(@primary-color, 20%);
        box-shadow: 0 0 5px tint(@primary-color, 20%);
      }
    }
  }

  &-mark {
    position: absolute;
    top: 10px;
    left: 0px;
    width: 100%;
    font-size: 12px;
    z-index: 3;
  }

  &-mark-text {
    position: absolute;
    display: inline-block;
    vertical-align: middle;
    text-align: center;
    cursor: pointer;
    color: #999;

    &-active {
      color: #666;
    }
  }

  &-step {
    position: absolute;
    width: 100%;
    height: 4px;
    background: transparent;
    z-index: 1;
  }

  &-dot {
    position: absolute;
    top: -2px;
    margin-left: -4px;
    width: 8px;
    height: 8px;
    border: 2px solid #e9e9e9;
    background-color: #fff;
    cursor: pointer;
    border-radius: 50%;
    vertical-align: middle;
    &:first-child {
      margin-left: -4px;
    }
    &:last-child {
      margin-left: -4px;
    }
    &-active {
      border-color: tint(@primary-color, 50%);
    }
  }

  &-disabled {
    background-color: #e9e9e9;

    .@{sliderClass}-track {
      background-color: @disabledColor;
    }

    .@{sliderClass}-handle {
      border-color: @disabledColor;
      background-color: #fff;
      cursor: not-allowed;
    }

    .@{sliderClass}-mark-text, .dot {
      cursor: not-allowed!important;
    }
  }

  // slider tooltip style
  &-tooltip {
    position: absolute;
    left: -9999px;
    top: -9999px;
    z-index: 4;
    visibility: visible;

    &-hidden {
      display: none;
    }

    &-placement-top { 
      padding: @tooltip-arrow-width 0 @tooltip-distance 0;
    }

    &-inner {
      padding: 6px 0;
      width: 24px;
      height: 24px;
      font-size: @font-size-base;
      line-height: 1;
      color: @tooltip-color;
      text-align: center;
      text-decoration: none;
      background-color: @tooltip-bg;
      border-radius: @border-radius-base;
      box-shadow: 0 0 4px #d9d9d9;
    }

    &-arrow {
      position: absolute;
      width: 0;
      height: 0;
      border-color: transparent;
      border-style: solid;
    }

    &-placement-top &-arrow {
      bottom: @tooltip-distance - @tooltip-arrow-width;
      left: 50%;
      margin-left: -@tooltip-arrow-width;
      border-width: @tooltip-arrow-width @tooltip-arrow-width 0;
      border-top-color: @tooltip-arrow-color;
    }
  }
}