用纯css创建一个三角形
.triangle{
0;height: 0;
border-left: 60px solid transparent;
border-right: 60px solid transparent;
border-top: 120px solid red;
}
.triangle{
0;height: 0;
border-left: 60px solid transparent;
border-right: 60px solid transparent;
border-top: 120px solid red;
}