div css导航二级菜单

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>CSS Navigation Menu</title>
    <style>
        body {
            font-family: Arial, sans-serif;
        }
        .nav {
            list-style: none;
            padding: 0;
            margin: 0;
            background-color: #f1f1f1;
        }
        .nav li {
            display: inline-block;
            position: relative;
        }
        .nav a {
            display: block;
            padding: 10px 20px;
            text-decoration: none;
            color: #333;
        }
        .nav ul {
            display: none;
            position: absolute;
            top: 100%;
            left: 0;
            background-color: #fff;
            box-shadow: 0 8px 16px 0 rgba(0,0,0,0.2);
        }
        .nav ul li {
            display: block;
        }
        .nav li:hover > ul {
            display: block;
        }
    </style>
</head>
<body>
    <ul class="nav">
        <li><a href="#">Home</a></li>
        <li><a href="#">About</a>
            <ul>
                <li><a href="#">Team</a></li>
                <li><a href="#">History</a></li>
            </ul>
        </li>
        <li><a href="#">Services</a>
            <ul>
                <li><a href="#">Web Design</a></li>
                <li><a href="#">SEO</a></li>
            </ul>
        </li>
        <li><a href="#">Contact</a></li>
    </ul>
</body>
</html>