理解弹性盒子

效果图

弹性盒子

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<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>理解弹性盒子</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }
        li {
            list-style: none;
        }
        a {
            text-decoration: none;
            color: #aaa
        }
        a:hover {
            color: red;
            text-decoration: underline;
        }
        .myjd a:hover {
            color: red;
            text-decoration: underline;
            background-color: #fff;
        }
        .myjd:hover ul {
            background-color: #fff;
            display: block;
        }
        nav {
            height: 50px;
            margin: 0 auto;
            background: #ccc;
        }
        nav>ul {
            box-sizing: border-box;
            display: flex;
            justify-content: center;
            align-items: center;
        }
        nav>ul>li {
            position: relative;
            margin: 10px 20px;
        }
        .jd-group ul {
            position: absolute;
            background: #fff;
            left: 0px;
            display: none;
        }
        .jd-group ul>li {
            padding: 10px 10px;
            width: 90px;
        }
    </style>
</head>
<body>
    <nav>
        <ul>
            <li><a href="">我的订单</a></li>
            <li class="myjd">
                <a href="">我的京东</a>
                <div class="jd-group">
                    <ul>
                        <li><a href="">我的京豆</a></li>
                        <li><a href="">我的优惠券</a></li>
                        <li><a href="">我的白条</a></li>
                        <li><a href="">我的理财</a></li>
                    </ul>
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            <li><a href="">手机京东</a></li>
            <li><a href="">网站无障碍</a></li>
        </ul>
    </nav>
</body>
</html>