太极(纯css)

<style>
        *{
            margin: 0;
            padding: 0;
        }
        html,body{
            width: 100%;
            height: 100%;
        }
        div{
            margin: 100px;
            width: 100px;
            height: 200px;
            border-radius: 50%;
            background-color: white;
            border-right: 100px solid black;
            /* box-shadow 水平偏移 垂直偏移 模糊度 阴影半径 颜色 */
            box-shadow: 0 0 50px 5px black;
            position: relative;
        }
        /* content:""; 撑开容器*/
        div::after{
            width: 100px;
            height: 100px;
            position: absolute;
            content: "";
            z-index: 1;
            top: 0;
            left: 50%;
            border-radius: 50%;
            background-color: white;
            box-shadow: 0 100px 0 black;
        }
        div::before{
            width: 30px;
            height: 30px;
            position: absolute;
            content: "";
            z-index: 2;
            top: 15%;
            left: 85%;
            background-color: black;
            border-radius: 50%;
            box-shadow: 0 110px 0 white;
        }
    </style>

结果展示：

taiji.png