Can’t add POPUP window properly

Hi! I try to add simple popup window on the page. But it doesn’t look properly
z-index doesn’t work as it should be
Here the print screen of this popup:
https://snipboard.io/CIxRMP.jpg

And here is proper view of popup in the Nirvana Theme:
https://snipboard.io/qURfre.jpg

I have tryed many different popups. Situation is the same.

What can I do?

Website: imacros.stepfor.top/fb-post-group-macc