html实现导航栏

    * {
            margin:0;
            padding:0;
        }
        ul {
            list-style: none;
        }
        body {
            height: 100vh;
            display: flex;
        }
        ul {
            display: flex;
            margin: auto;
        }
        li {
            position: relative;
            padding: 20px;
            font-size: 24px;
            color: #000;
            line-height: 1;
            cursor: pointer;
        }
        li::before {
            content: "";
            position: absolute;
            top: 0;
            left: 100%;
            width: 5%;
            height: 100%;
            border-bottom: 2px solid #000;
            transition: 0.2s all linear;
        }
        li:hover::before {
            width: 100%;
            top: 0;
            left: 0;
            transition-delay: 0.1s;
            z-index: -1;
        }
        li:hover ~ li::before {
            left: 0;
        }
        li::before {
            width: 0%;
        }

以上是css部分，下面是html部分： 

 <ul>
            <li>首页</li>
            <li>商城特惠</li>
            <li>个人中心</li>
            <li>购物小车</li>
        </ul>