Dark settings dialog

[dkavlakov]

I really like the extension and consider it the best gesture extension right now, especially due to it's userscript support. It however has one huge disadvantage - for people with light sensitive eyes like me working with the stock settings dialog on a decently modern monitor is physically painful experience, as it is basically same as having to read small text, written on a huge working LED light panel. Can you please add dark mode to it?