Animated Link Underline

A pure CSS link hover animation using pseudo elements. :)

HTML

<a href="#">This is a link</a>

CSS

a {
    color:#000000;
    text-decoration:none;
    position:relative;
}
a::after {
    content:'';
    display:inline-block;
    width:0;
    height:8px;
    background:#E23425;
    position: absolute;
    left: 0px;
    bottom:-8px;
    transition:0.1s ease-in;
}
a:hover::after {
    width:100%;
}