Works fine, though I would love options to change colour and width.
It's thinner than the standard scrollbar which feels a little bit off and is bugging me. a slider or an input field to change the width shouldn't be too difficult to add.

Doesn't work in full screen videos such as YouTube, scroll bars overlays on top of video and needs to be fixed. Other than that, looks and works good

Please remove or hide scrollbar in fullscreen YouTube view. Your addon prevent YT from hide side scrollbar.