Make Bottom Nav sticky?

Hey guys!

So I’ve managed to do the bulk of the work in my custom header adventure, but am stuck with the sticky part of it since the nav menu isn’t already at the top of the page.

Basically how can I enable this sticky feature to just the bottom nav menu so that when a user scrolls down and the nav menu hits the top of the browser window it becomes sticky?

(I don’t want the header portion of it that contains the logo and social icons to be sticky, just the nav menu) :)

Thanks in advance, you guys are the best!!