I think you are all forgetting to ask
@W1zzard a question before you ask these questions. I am not a coder, so I don't know the answer to this question, but it may simply be A LOT of work/coding to make something like this happen? I don't know. Keep in mind, he is basically a one man show for this website with a team of moderators to help... at least that is how I percieve the site, I may be wrong on that.
In which case, crack your whip and make the worker bees work! lol jk, I actually don't care one way or another about a dark mode, but I think
@qubit is correct, if you have a dark mode button on the forum front page or something where its easily seeable by the masses and not buried in settings, it might increase traffic to the site. it's not a bad idea.
edit: I just enabled dark mode in Chrome, under the experiments section. why don't you all just do this? looks good enough to me.