I used to love dark themes I tend to like horror a lot, and being a metalhead, well, let’s just say that most the sites I frequented were 50 shades of black.
It was not until I started doing things more"professionally" and having people read my prose that it was pointed out to me that reading light on dark is a lot of strain for many people. Some even went so far as to highlight all the text to do their own quick-fix and invert the color scheme.
I think that it might work in choicescript, since the text is large and friendly (at least on the pc) and the chunks of text are easily digestible, but it is hard to say before I see it.
I think the big question to ask is WHY it is important to have a different color scheme than the standard? What is the purpose? What would be achieved that can’t be achieved with the grey on whitish that they have now?
The only case I can imagine would be horror based stories, where the darkness might add a little something. Still… doubtful.
You want as few barriers between the text and the reader as possible, so stay away from lines and stuff, they just distract.
On the other hand, it also depends on your computer settings. Some people have said that this forum is too bright for them, my screen is probably set darker, which would also mean that this might be a reason why I can’t handle dark themes. Most sites are bright and light, so I turn down my light settings a little to make them comfortable to look at,
Perhaps a simple choice button to set color theme? Like #custom and #original? That would please everybody.