I realize there are a few convoluted ways you can fake a dark mode changing your preferences and your system settings, but I think an actual nightmare option would be very pleasant. I frequently work in the evening or in low light environments and I find the brightness of the default Scrivener very jarring. With an actual dark mode, we would have the ability to swap back and forth dependent on the situation.
With your user name, asking for a “nightmare” mode is very apt! 
I’m afraid a Dark or Night Mode in Scrivener for macOS is very unlikely, though. It’s not that it wouldn’t be nice - it would - but it is just impractical given the huge number of UI elements in Scrivener. It would require building in a switch for literally thousands of UI elements. It would also require a second set of icons for all the toolbar icons and anything els that would not work against a dark background. Not only that, but because the user can choose to customise the colours of many parts of the UI, it would render many of the Preferences inactive when switched on - unless there was a second large set of preferences for Dark Mode.
As you say, though, you can already change Preferences. And there is even the option to save different theme Preferences via the Preferences panel (“Manage…”) at the bottom. I wonder if just an easier way of switching between themes might be a good option for this, perhaps having a “Themes” submenu in the “Scrivener” menu… Hmm.
All the best,
Keith
One option that some people like is to use the Apple -> System Preferences -> Accessibility -> Display tab to invert colors. That has the advantage of being system wide, so you aren’t blinded by the “normal” display when you leave Scrivener.
Katherine
If somebody created a theme, could it be shared?
Somebody could! There is a thread now dedicated to this:
A dark mode wouldn’t need to change all the UI elements. Anything that is already adjustable by the user doesn’t need to be affected as we can do that ourselves through themes. All a dark mode needs to do is to switch the non-user adjustable elements (toolbar, etc) to a darker version.
Yes, that would still need some revised icons, but it’s not quite as awkward as it could be.
Of course, having the dark mode and light mode able to have their own default themes (if users have created any) would be a bonus.
Er, not awkward to change the dozens of icons and built-in macOS elements? Yeah, sounds real simple and the sort of thing I can do in minutes.
Pro tip: anything involving an alternative version of all icons is not going to happen.
Out of morbid curiosity, and a fondness for the days of ResEdit, how many resources are we talking about overall, KB? Hundreds? Thousands? I get a headache just thinking about it.
Great! 
You’re talking around 350 images that would need variants, and so around 175 code switches for that (since all images have two variants, Retina and non-Retina). Then every background element such as header bars, footer bars, inspector bars, split view dividers and so on would need alternative drawing code. Anything using colour such as labels would need alternative ways of drawing to work with dark backgrounds. Custom button selections would need alternative drawing routines. Apple elements with no dark variant, such as outline and table header bars, would need overriding and custom drawing applied. And so on…
It took the best part of a month to implement Dark Mode in iOS, which has a fraction of the UI elements the macOS version has. So you can imagine how that would play out for macOS!
A more feasible approach would be to offer an option for using a darker grey for headers, footers and inspector backgrounds that still works with current colours and elements, and then to allow theme Preferences to do the rest.
Having read all the posts in this thread I think you are all missing the most obvious solution:
Turn on the light!
(… or go to bed)
That way Scrivener won’t be perceived to be jarring. 
Or OSX’s built-in Night Shift function.
But, hey, the ultimate solution for dark mode is the right pair of super-chromatic sunglasses. Because, let’s face it, there are a whole lot of settings beyond the computer screen that you really need to be able to throw into Dark Mode.*
-gr
- It would also be useful if the glasses would turn completely opaque in times of peril.
Well I was hoping it might be a feature in future iterations of the software, but it sounds like that won’t be the case. Thanks for all the replies everyone.
Also, my personal attempt at a dark mode:
That’s right around what I figured – thank you for going into more detail.
Well, since you mentioned it…I wasn’t going to post anything about this because you just released the new version and don’t need any buzzkill, but strangely I was thinking of just this issue on the drive to my workshop today.
I, for one, would love to have a themes manager of some sort where I could load user-created color schemes. Setting them myself is a sort of pain in the butt, plus to do it right will take real work to get the colors just so…
As you know, in programming editors it is common to have various pre-installed and user-created themes to suit individual preferences that are easy to download and share.
Anyway, one vote for a Themes manager…
–Darin
Just want to say how GREAT dark mode is in iOS. Thanks for it.
Would you be willing to share it? (Options → Appearance → Manage → Save Preferences)
Would it make sense to combine a themes manager with (or mimic) the Layouts menu and control window? I like the idea of themes, but more accessible way to swap them out/save them would make the difference between me using the feature and not. They’re kind of related in that they affect the appearance of the Scrivener window, and being able to swap layouts and themes at the same time or with the same UI would be nice.