I might have become blind. Z-index stopped making sense

Never had trouble with z-index - I have used Webflow for at least 4 years - almost every day, but for some reason, I can’t wrap my head around this Z-index situation.

I have a few sections on a page that have the same button, that opens an overlay. That overlay won’t be on top of the content in the sections around it - just some items are above - and the weird thing is that all sections are the same. There is no Z-index set to any elements other than the overlay.

Hope you can help! :sweat_smile:

Link: Webflow - Almenr

Have named the items for ease of inspection:
Overlay_wrapper
Overlay_opener
Overlay_opener_btn
The_overlay
Overlay_content

Example: The image with the house should not be visible