css 底部导航边框选择性插入线条

 

.bottom-navgation {
    width: 100%;
    height: 3.5rem;
    background-color: #ededed;
    position: fixed;
    bottom: 0;
    display: flex;
    flex-direction: row;
    // 子容器列表
    .item {
      width: 25%;
      height: 100%;
      display: flex;
      justify-content: center;
      align-items: center;
    }
    .item:not(:nth-child(1)) {
      position: relative;
      &::before {
        content: '';
        position: absolute;
        left: 0; 
        top: 9px;
        background-color: #A9A9A9;
        width: 1px;
        height: 40px;
      }
    }
  }