css三角制作（二十课）
代码：
<style>/* 边框原理 */.box1 {width: 0;height: 0;border-top: 100px solid pink;border-bottom: 100px solid blue;border-left: 100px solid yellow;border-right: 100px solid greenyellow;}/* 三角制作 */.box2 {width: 0;height: 0;border: 100px solid transparent;border-right: 100px solid greenyellow;margin: 5px;}.jd {position: relative;width: 100px;height: 100px;background-color: pink;}.jd span {position: absolute;right: 10px;top: -25px;width: 0;height: 0;border: 10px solid transparent;border-bottom: 10px solid greenyellow;margin: 5px;}</style>
</head><body><div class="box1"></div><div class="box2"></div><div class="jd"><span></span></div>
</body></html>