Icons displaying BEHIND header element, no luck with z-index

If anyone could help me sort out why the social media links in the header (LINK) are displaying behind the menu rather than on top of it, I’d sincerely appreciate it!

I adjusted it to show slightly below the element I’d like it on top and in-line with, so that you can visibly see what’s going on.

I’ve played around with it quite a bit, but all of the usual fixes are having me come up blank (z-index, etc.)!

Help is as always, much appreciated.

Thank you!