Dark Scrollbar for YouTube [Deprecated] von Hexandcube

This simple add-on changes the theme of the scrollbar on YouTube from light to dark.
It uses a dynamic scrollbar feature in Firefox that automatically makes the scrollbar dark, when website's body background property is set to a dark color.

This addon has been deprecated, and is no longer needed, since YouTube added official support for Firefox's automatic dark scrollbars.

Works on Firefox 72 or newer.