No, there is no default option in the current forum software, maybe it would be available in the new forum when we eventually migrate.
You can check out this thread -
List of Bitcointalk.org Userscripts/ Add-ons if you are comfortable with userscripts or add ons.
Some browsers like Firefox, also support default dark theme.
Cool, I wasn't aware of any future migrations, looking forward to that. I'm seeing a lot of features there that I didnt even think of but they are nice QoL changes. Is there an expected date for the migration?
Some of those makeshift dark mode changes do have an ugly aesthetic.
There are some (browser) extensions that attempt to create universal dark mode across sites, and you may find better cohesion with those if privacy is not an issue. Despite what I expected, it turns out a lot of Bitcoiners don't mind that, so check them out if it applies to you.
I'm aware of extensions but sometimes they flat out don't work, or they create an ugly theme, poor contrast, etc. The flipped colors don't work out and are sometimes unreadable. Do you have a recommended extension that you use personally for chrome?