*不使用图标，绘制三角形图案（简单小demo）
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>HTML5与css3之绘画出三角形</title>
</head>
<style type="text/css">
*{
margin: 0;
padding: 0;
text-decoration: none;
}
.triangle_up{
width: 0px;
height: 0px;
border: 100px solid transparent;
border-bottom: 100px solid red;
}
.triangle_left{
width: 0px;
height: 0px;
border: 100px solid transparent;
border-right: 100px solid red;
}
.triangle_right{
width: 0px;
height: 0px;
border: 100px solid transparent;
border-left: 100px solid red;
}
.triangle_bottom{
width: 0px;
height: 0px;
border: 100px solid transparent;
border-top: 100px solid red;
}
</style>
<body>
<div class="triangle_up"></div>
<div class="triangle_left"></div>
<div class="triangle_right"></div>
<div class="triangle_bottom"></div>
</body>
</html>
如图效果：
