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](https://preview.webflow.com/preview/penina-levy?utm_medium=preview_link&utm_source=designer&utm_content=penina-levy&preview=bb38bb86ec53050273b32f87e2c8d326&workflow=preview)
(how to share your site Read-Only link)