Snippet: Add Border Animation Hover on Header One Menu Links

#site-navigation .dropdown-menu > li > a > span.link-inner {
    position: relative;
}
#site-navigation .dropdown-menu > li > a > span.link-inner:after {
    position: absolute;
    bottom: 0px;
    content: "";
    background: #4a97c2;
    width: 0;
    height: 2px;
    left: 0;
    transition: 0.3s all;
}

#site-navigation .dropdown-menu > li > a > span.link-inner:hover:after {
    width: 100%;
}