javascript - transition height auto 过渡动画-PHP中文网问答

1.为什么收缩时，没有动画效果？
2.代码
<!DOCTYPE html>
<html lang="en">

<head>
    <title></title>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <style>
        * {
            transition: all .6s;
        }

        .container {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            height: 100px;
            max-height: 100px;
            width: 100px;
            margin: 5px auto;
            background: RGBA(0, 43, 54, 0.80);
            overflow: hidden;
            text-align: center;
        }

        .container:hover {
            height: auto;
            max-height: 100%;
            bottom: 0px;
        }
    </style>
</head>

<body>
    <p class="sketch">
        <p class="container">
            <!--<a id="switch" href="javascript:void(0)">开关</a>-->
        </p>
    </p>
    <!--<script>
        const classList = document.querySelector('.container').classList;
        document.querySelector('#switch').addEventListener('click', function (e) {
            if (classList.contains('expand')) {
                document.querySelector('.container').classList.remove('expand');
            } else {
                document.querySelector('.container').classList.add('expand');
            }
        });
    </script>-->
</body>

</html>
3.在线Demo(己解决)