You will need to install a user script manager extension to install this script.
Automatically hides the top and bottom bar when paused.
Makes it easier to read text on the top/bottom that is normally hidden by the controls.
Limitations: Doesn't work in fullscreen when paused because the cursor only goes away when the video is playing. If you have a multi monitor setup this would be a non-issue since you can just move the cursor to the other display.