css hover underline transition left to right
.link:after{
content: '';
position: absolute;
width: 0; height: 3px;
display: block;
margin-top: 5px;
right: 0;
background: #fff;
transition: width .2s ease;
-webkit-transition: width .2s ease;
}
.link:hover:after{
width: 100%;
left: 0;
background: #fff;
}