css标题栏滑动效果

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>CSS标题栏滑动效果</title>
    <style>
        body {
            margin: 0;
            font-family: Arial, sans-serif;
        }
        .header {
            position: fixed;
            top: 0;
            width: 100%;
            background-color: #333;
            color: white;
            padding: 10px 20px;
            transition: top 0.3s;
        }
        .header.sticky {
            top: 0;
        }
        .content {
            padding: 100px 20px;
            height: 2000px; /* 仅用于演示滚动效果 */
        }
    </style>
</head>
<body>
    <div class="header" id="header">
        我的网站标题栏
    </div>
    <div class="content">
        这里是页面内容...
    </div>

    <script>
        window.addEventListener('scroll', function() {
            const header = document.getElementById('header');
            if (window.scrollY > 50) {
                header.classList.add('sticky');
            } else {
                header.classList.remove('sticky');
            }
        });
    </script>
</body>
</html>