html：
<body>
<div class="triangle_up"></div>
<div class="triangle_left"></div>
<div class="triangle-top-left"></div>
<div class="box"></div>
</body>
1.利用transparent属性
.triangle_up{
width: 0;
height: 0;
border-left: 30px solid transparent;
border-right: 30px solid transparent;
border-bottom: 50px solid red;
}
triangle_up.png
.triangle_left{
width: 0;
height: 0;
border-top: 50px solid transparent;
border-bottom: 50px solid transparent;
border-left: 100px solid red;
}
triangle_left.png
.triangle-top-left {
width: 0;
height: 0;
border-top: 100px solid red;
border-right: 100px solid transparent;
}
triangle-topleft.png
2.利用border属性
.box{
width: 0;
height: 0;
border-top: 50px solid black;
border-right: 50px solid red;
border-bottom: 50px solid blue;
border-left: 50px solid orange;
}
box.png,将其他三块换成白色即可
