10.10 形变中心点position: absolute; /* 形变中心点百分比 50% 50% 像素单位200p

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
            list-style: none;
        }
        ul{
            width: 100px;
            height: 100px;
            border: 1px solid royalblue;
            margin: 30px auto;
        }
        ul li{
            width: 100px;
            height: 100px;
            position: absolute;
            /* 形变中心点
            百分比 50% 50%
            像素单位200px 0
            位置关键字 center top bottom            
            
            */
            transform-origin: center bottom;
        }
        ul>li:first-child{
            background-color: yellow;
            transform: rotate(30deg);
        }
        ul>li:nth-child(2){
            background-color: blue;
            transform: rotate(45deg);
        }
        ul>li:last-child{
            background-color: red;
            transform: rotate(60deg);
        }
    </style>
</head>
<body>
    <ul>
        <li></li>
        <li></li>
        <li></li>
    </ul>
</body>
</html>