<a href="#">大幅度发甲方</a>
.demo1{
position: relative;
text-decoration: none;
font-size: 20px;
color: #333;
}
.demo1:before{
content: "";
position: absolute;
left: 50%;
bottom: -2px;
width: 0;
height: 2px;
background: #4285f4;
transition: all .3s;
}
.demo1:hover:before{
width: 100%;
left: 0;
right: 0;
}
