Page Dark by Marnes

This addon won't be maintained further. I'm shelving this project due to lack of interest/utility and too much burden. The addon will remain available for download as long as the store allows, and the source on gitlab will also remain available to fork.
I do have a greasyfork account you can check out, and you can get new versions of CSL, DID, and IBCP there!

Available for Chrome too.

Functionality

Page Dark covers the webpage with a black screen when you click the toolbar button or trigger the hotkey. Everything except media like videos or games, frames and Flash objects will be hidden by it. This allows you to watch online videos, play Flash games, etc in a much more enjoyable way.

FAQ

• How do I configure the hotkey?
  Via your browser's generic addon hotkey settings.

Please rate/review/donate! :)
A lot of time and work goes into creating my addons, and making changes or troubleshooting issues for users.

Problem, bug, broken, question, request?
Per Mozilla policy, only an evaluation of an addon's entire function with reasonable expectations is a proper review. Vague complaints or 1-star ratings for single reasons are considered spam, as are false claims about the addon not working at all. For more detailed discussions, use the linked support site or email.