老师帮忙看下代码嘛谢谢

来源：2-18 编程练习

咸鱼王派大星

2021-03-10 10:31:55

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>2-9</title>
    <style type="text/css">
        div {
            font-family: Arial;
            font-size: 72px;
            font-weight: bold;
            position: fixed;
            left: 50%;
            bottom: 40px;
            width: 30px;
            height: 30px;
            margin: auto;
            /*此处写代码*/
            animation: r 0.5s linear 0s infinite alternate;
        }
        @keyframes r {
            from{
                transform:rotate(90deg) translateX(0);
            }
            to{
                transform:rotate(90deg) translateX(20px);
            }
        }
    </style>
</head>
<body>
    <div>&gt;</div>
</body>
</html>