Dynamic menu drop-down background color change?

Forgive me for my knowledge of code is a bit lacking... on my site's main navigation, it is set to "dynamic", and when scrolling down the page, the menu then turns to a solid black background. Using inspector I am utterly baffled by the miles of code and can't figure out how I change this in custom-CSS so that I can adjust that color/opacity to better match the template? We don't want any black backgrounds as the site revolves around healthcare. 

I think the site's template is Clover, but I don't see a way to check that in the interface.

(edit: Forgot to add, any assistance would be greatly appreciated and thanks!)   

I figured out that I can change it in site styles->edit theme->darkest1 and changing Section Background / Background Overlay. Not sure how to marked resolved.