Hierarchy with two fixed elements

If I have two fixed elements on a page, how do I control which element is in the foreground and which in the background when those two elements intersect?

Here on my site: I want the shapes to tuck under the fixed navigation bar as I scroll.

TIA!


Here is my site Read-Only: [LINK](Webflow - Penina Levy's Portfolio)
(how to share your site Read-Only link)