代码大体解读
一、
span{ /*利用边框做一个三角形*/
border-color:transparenttransparentrgba(255,255,255,0.5)transparent;/*每个span下方设置颜色,其余边透明*/
border-width:173.2px100px;
border-style:solid;
width:0;
height:0;
position:absolute;
left:50%;
margin-left:-100px;
top:50%;
margin-top:-346.4px;
}
span:before{ /*利用边框在span中做一个三角形,实现嵌套,让span变成边框,span:before变成要显示的东西*/
content:'';
border-color:transparenttransparentrgba(0,123,123,0.5)transparent;/*设置每面的颜色*/
border-width:165.2px92px;
border-style:solid;
width:0;