vant/packages/vant-css/src/tab.css

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

@component-namespace van {
  @b tabs {
    position: relative;

    @m col-2 {
      .van-tab {
        width: 50%;
      }
    }

    @m col-3 {
      .van-tab {
        width: 33.33333333333333%;
      }
    }

    @m col-4 {
      .van-tab {
        width: 25%;
      }
    }

    @m col-5 {
      .van-tab {
        width: 20%;
      }
    }

    @e nav {
      overflow: hidden;
      transition: transform .5s cubic-bezier(.645, .045, .355, 1);
      position: relative;

      @m line {
        height: 44px;
        background-color: $c-white;
        &::after {
          @mixin border-retina (top);
          @mixin border-retina (bottom);
        }
        @b tabs-nav-bar {
          display: block;
        }
      }

      @m card {
        height: 28px;
        margin: 0 15px;
        background-color: $c-white;
        border-radius: 2px;
        border: 1px solid #666666;
        overflow: hidden;

        .van-tab {
          color: #666666;
          line-height: 28px;
          border-right: 1px solid #666666;
          &:last-child {
            border-right: none;
          }
          &.van-tab--active {
            background-color: #666666;
            color: $c-white;
          }
        }
      }
    }

    @e nav-bar {
      z-index: 1;
      position: absolute;
      left: 0;
      bottom: 0;
      height: 2px;
      background-color: #f13e3a;
      transition: transform .3s cubic-bezier(.645, .045, .355, 1);
      transform-origin: 0 0;
    }
  }

  @b tab {
    color: $c-black;
    font-size: 14px;
    line-height: 44px;
    box-sizing: border-box;
    transition: color .3s cubic-bezier(.645, .045, .355, 1);
    cursor: pointer;
    text-align: center;
    float: left;

    @m active {
      color: #FF4444;
    }

    @e pane {
      display: none;

      @m select {
        display: block;
      }
    }
  }
}