.expand{
position:relative;
text-decoration:none;
display:inline-block;
}
.expand:after {
display:block;
content: '';
border-bottom: solid 3px #000;
transform: scaleX(0);
transition: transform 250ms ease-in-out;
transform-origin:100% 50%
}
.expand:hover:after {
transform: scaleX(1);
transform-origin:0 50%;
}