<div class="transform">42.48%</div>//转化.transform {position: relative;width: 70px;height: 26px;background-color: #dcdfe6; /* 长方形的颜色 */display: flex;justify-content: center;align-items: center;font-family: PingFangTC-Medium;font-weight: 500;font-size: 14px;color: #303133;}.transform::after {content: "";position: absolute;top: 26px; /* 三角形位于长方形下方 */left: 0px;width: 0;height: 0;border-left: 35px solid transparent;border-right: 35px solid transparent;border-top: 6px solid #dcdfe6;}

参考：

纯CSS画基本图形（矩形、圆形、三角形、多边形、爱心..）_css结构框图怎么画-CSDN博客