I think a lot of people would appreciate it, I know I will.
I would personally keep it on permanently - I like everything to be dark mode if I can have it.
I do have a couple of browser thingeys I use, but the one I use makes it look like a patchy mess and the other one I use has to be manually turned on when I need it and I only got it for these forums since the other one I use does such a bad job of it.
If there is a dark mode for these forums that I simply havent been able to find then I am sorry... but some guidance would be appreciated...
If it is not possible and there isnt one, maybe someone has a suggestion for a dark mode browser addon that does a good job automatically.
currently the ones I am using are Firefox "Custom Dark mode" which is the one that makes a patchy mess. It is fully custom in that you have sliders, but putting them anywhere along the whole spectrum doesnt do a good job, it can be set to on or off for specific webpages, so I turn it off for pages that have a dark mode setting, also the fully negative version makes the page look like a camera film negative which is why I got the second one Firefox "Dark mode lite" which seems to keep the colours of the images while making all the whites black and visa versa.
Operas built in dark mode works pretty good on this site
There's no official dark theme for SMF, and I'm not keen on installing custom themes that make maintenance of the forum any more difficult, sorry.