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.

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.

The problem here is the developing countries that seek such help from China are gullible, this is mostly a corrupt deal, and this is a first hand view. The corrupt leaders from those country -of which am a citizen of - strikes deals with China for loans in huge amounts -loans that never serve any use - and insure use part of their sovereignty as a collateral, off cause China would oblige and sign off such loans already knowing the state of the country.

This countries are losing there sovereignty to China, this might not be paid now but in generations China would control large areas of Africa, which is becoming habitual debtors to China.

This can be solved by
+ Borrowing what can be paid back at the stipulated time
+ Using what was borrowed for a good use,
+ Try killing/stoping the urge to borrow

Does it do something that Bitcoin can't?  If not, don't invest.
Is there a founder's reward?  If not, don't invest.
Is the distribution fair?  If not, don't invest.
Is it an open source project anyone can contribute to?  If not, don't invest.

I generally believe that 95% of your crypto holdings should be in Bitcoin, but a couple I wouldn't oppose seeing money thrown at are: Grin, Ravencoin, & Namecoin.