You have a great dark theme for the webinterface, why not in the forum?
Well, there are not much responsive themes for this forum. I don't have the time to create own themes for this forum.
Yeah i have to acknowledge, you didn't choose a fancy nor popular forum software =D
Now there is a darker theme, just change to the UX theme in the "Look and Layout" section at your forum profile.
Oh, i see. Thank you :)