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来源：2-18 编程练习

慕UI4313976

2021-03-08 21:36:34

<!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;
            right: 0;
            left: 0;
            width: 30px;
            height: 30px;
            margin: auto;
            transform: rotate(90deg);
            /*此处写代码*/
            animation: down 2s ease 0.5s infinite;
        }
        @keyframes down{
            0%{
                transform:translateY(0) rotate(90deg);
            }
            25%{
                transform:translateY(20px) rotate(90deg);
            }
            50%{
                transform:translateY(0) rotate(90deg);
            }
            100%{
                transform:translateY(20px) rotate(90deg);
            }
        }
    </style>
</head>
<body>
    <div>&gt;</div>
</body>
</html>