Lightbox (Webflow native)

Ladies and Gents, im stuck!

Having a native lightbox running on a client’s site, i’ve added a button being showed in lightbox, but i can’t figure out how to trigger once lightbox is being closed. so i want to have the button shown only when lightbox is open and hidden when closed. I put a placeholder red div-box in the top-left corner.

Thanks in advance for all of your help!!

Cheers
Raph

Here is my site Read-Only: https://ssp-2021-10.webflow.io/ssp-2021-p-landscape