css 梯形
.div{
position:absolute;
left:0;
top:0;
line-height: 30px;
color:#fff;
/*border:1px solid #00A1FC;*/
border-bottom: 100px solid #00A1FC;
border-left: 0px solid transparent;
border-right: 50px solid transparent;
height: 0;
width: 150px;
text-align:center;
}