Is it possible to change HTML of header and footer and message details on the forum?

I’m looking to alter the header as well. Is there any way – preferably without using Javascript – to update the top row (inside <header class="d-header clearfix"> after the title class) on desktop?

The Envato solution is unacceptable because they’re wasting a substantial amount of vertical space. We have this huge bar here that’s completely empty on Desktop browsers!

That’d be a great place to put some key links.