Settings window doesn't follow appearance of the rest of the page

[nsilvestri]

Currently the settings window does not follow the appearance rules applied to the rest of the page. It would be much more visually cohesive if the settings window followed the appearance of the rest of the page (and wouldn't scorch my eyeballs at night because it's all white).

[ibillingsley]

I didn't want the user to be able to accidentally make the settings unreadable and have difficulty changing them back. I might add a simple light/dark toggle for the settings window and context menu.