css三角图标

案例三角：

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box {
            margin: 100px auto;
            position: relative;
            height: 100px;
            width: 50px;
            background-color: pink;

        }

        .box span {
            position: absolute;
            right: 15px;
            top: -10px;
            height: 0;
            width: 0;
            /* 为了照顾兼容性 */
            line-height: 0;
            font-size: 0;
            border: 5px solid transparent;
            border-bottom-color: pink;
        }
    </style>
</head>

<body>
    <div class="box">
        <span></span>
    </div>
</body>

</html>