.link-underline {
    border-bottom-width: 0;
    background-image: linear-gradient(transparent, transparent), linear-gradient(#fff, #fff);
    background-size: 0 3px;
    background-position: 0 100%;
    background-repeat: no-repeat;
    transition: background-size .5s ease-in-out;
}

.link-underline-black {
    background-image: linear-gradient(transparent, transparent), linear-gradient(#631D4C, #631D4C)
}

.link-underline:hover {
    background-size: 100% 3px;
    background-position: 0 100%
}

#navbar {
    width: 50%;
    height: 100%;
    position: fixed;
    z-index: 1;
    top: 0;
    left: 0;
    overflow-x: hidden;
    transition: 0.5s;
}

#navbar.close {
    left: -50%;
}