Can you get it to successfully work on this page?

Zapping elements gets rid of the pop-up, but also makes scrolling impossible.

Yes I was able to get it to successfully work, you just have to keep zapping elements until the page displays properly. This also works on instagram if you're viewing without an account, though they seem to shadowban ip's now as I can't view accounts until after a few days.

Could you please paste your custom filter rules for it?

I tried the keep-zapping approach, and eventually got rid of the pop-ups, but then was unable to actually scroll through the page and read the article.

nationalgeographic.com##html:style(height:100%!important;overflow:scroll!important;position: static !important)

nationalgeographic.com##body:style(height:100%!important;overflow:scroll!important;position: static !important)

I added this to my custom filter list, and it did not get rid of the sign-up pop-up.

You can use the zapper tool for that

Like I said in this thread, I tried and could not get it working. I am curious how other people got it working, since we are using the same tool and seeing the same webpage.