CODE EXAMPLE FOR CSS

underline text

.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%;
}