Can I get a social link to appear on mobile only?

Hi,
There is almost nothing that you say it can't be done!

Use this code in Design -> Custom CSS

@media screen and (max-width: 640px){
.Header--top,[data-nc-base="header"] [data-nc-group="top"] {
    display: block;
    padding: 0;
}
.enable-load-effects .Site.loaded .Header [data-nc-container="top-left"],[data-nc-base="header"] [data-nc-container="top-right"] [data-nc-element="primary-nav"],[data-nc-base="header"] [data-nc-container="top-right"] [data-nc-element="secondary-nav"]{
    display: none;
}

[data-nc-base="header"] [data-nc-container="top-right"] [data-nc-element="social"] {
    position: absolute;
    top: 24px;
    right: 70px;
}
}

Please use the like button if it helps you!

Best,
Leopold