<html>
<head>
<meta charset="UTF-8">
<title>纯CSS绘制三角形（各种角度）</title>
<style type="text/css">
div{
margin:10px;
}
.triangle-topright {
width: 0;
height: 0;
border-top: 100px solid red;
border-left: 100px solid transparent;
}
.triangle-up {
width: 0;
height: 0;
border-left: 50px solid transparent;
border-right: 50px solid transparent;
border-bottom: 100px solid red;
}
.triangle-down {
width: 0;
height: 0;
border-left: 50px solid transparent;
border-right: 50px solid transparent;
border-top: 100px solid red;
}
.triangle-left {
width: 0;
height: 0;
border-top: 50px solid transparent;
border-right: 100px solid red;
border-bottom: 50px solid transparent;
}
.triangle-right {
width: 0;
height: 0;
border-top: 50px solid transparent;
border-left: 100px solid red;
border-bottom: 50px solid transparent;
}
.triangle-topleft {
width: 0;
height: 0;
border-top: 100px solid red;
border-right: 100px solid transparent;
}
.triangle-bottomleft {
width: 0;
height: 0;
border-bottom: 100px solid red;
border-right: 100px solid transparent;
}
.triangle-bottomright {
width: 0;
height: 0;
border-bottom: 100px solid red;
border-left: 100px solid transparent;
}
</style>
</head>
<body>
<div class="triangle-topright"></div>
<div class="triangle-topleft"></div>
<div class="triangle-bottomleft"></div>
<div class="triangle-bottomright"></div>
<div class="triangle-up"></div>
<div class="triangle-down"></div>
<div class="triangle-left"></div>
<div class="triangle-right"></div>
</body>
</html>
