HTML+CSS实现简易下拉菜单

使用html+css实现简易的下拉菜单

html代码如下：

  <ul class="menu">
        <li> <a href="#">Home</a></li>
        <li>
            <a href="#">  Html5  </a>
            <ul class="sub">
                <li><a href="#">  Html5  </a></li>
                <li><a href="#">  Html5  </a></li>
                <li><a href="#">  Html5  </a></li>
            </ul>
        </li>
        <li> <a href="#">News</a></li>
    </ul>

css代码如下：

   <style>
        * {
            margin: 0;
            padding: 0;
            list-style: none;
            text-decoration: none;
        }
        
        .menu {
            width: 1000px;
            height: 50px;
            margin: 50px auto;
        }
        
        .menu li {
            float: left;
            width: 200px;
            height: 40px;
            margin-right: 10px;
            background-color: pink;
            line-height: 50px;
            text-align: center;
        }
        
        .menu li a {
            display: block;
            width: 100%;
            height: 100%;
            color: #fff;
            font-size: 20px;
        }
        
        .menu>li:nth-child(2) {
            position: relative;
        }
        
        .sub {
            position: absolute;
            overflow: hidden;
            top: 40px;
            left: 0;
            height: 0;
            transition: 1s;
        }
        
        .menu>li:nth-child(2):hover .sub {
            height: 200px;
        }
    </style>

效果图：