How to set the default theme as dark?

[ticoeteco23gb]

Hello, I started using BF recently, but it seems like when I open and close the browser, the light theme is the default one.
It hurts my eyes, since I use my computer on the nighttime, and I shouldn't lower too much the brightness of the screen.

[yokoffing]

#285 (comment)

[ticoeteco23gb]

Thank you so much!! That's really helpful.