I almost made this same post a while back, I went through all the settings and couldnt find a way to change the layout colors so figured it was just stuck at this.. which it appears to be. I try to change all of the forums/socials I visit to BLACK background, as this greatly helps with eye strain when reading late at night (when I often get a chance to sit down and read a lot). even turning my laptop brightness down all the way sometimes isn't enough. I've often gotten headaches from reading this forum, when I am researching a topic and reading replies for an hour or so straight.
I'll just say that if it doesnt affect you, then please consider yourself lucky.. because it stinks and isn't enjoyable to have this issue. Some of the replies here over a simple request to change the layout (I can on EVERY SINGLE forum I visit besides this one), is mind boggling... "IT DOESNT AFFECT ME SO YOU CAN LEAVE" is the attitude I see. Like I said, consider yourself lucky that it doenst bother you.
Honestly if the information and people werent so great here, I wouldn't have stuck around. The headaches and eye strain are usually worth it.