footer a {
    position: relative;
}

footer a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -2px;
    left: 0;
    background: linear-gradient(to right, #DBBC42, #a09358);
    transition: width 0.3s ease;
}

footer a:hover::after {
    width: 100%;
}