Update: My firefox was broken. The extension works fine.

Ankit Ahuja has done a great job of improving this extension. I'm spoiled. Sometimes in other applications, I (mistakenly) want to change the interface, as if I were here in Firefox. Before the author fostered the extension, I was stuck in Chrome because that's where Stylebot was. Now it works in Edge too. Maybe a steep learning curve, and it's pretty deep, it's a techie thing for sure, but it's productive and very rewarding. BTW... Developer Tools (F12) can be helpful for using Stylebot (I mean using, not learning).

This extension finally available here allowed me to switch to Firefox, as it's my vital to-go way to eliminate all awful white backgrounds.

Very happy it has been ported!

Interesting