Give your site a dark mode your readers can switch on — one that reads properly on every page, without you restyling anything.
The complete list — what each part does and what it is there for.
Every stylesheet on the page is read and re-coloured, element by element, so a dark page still looks like your site rather than like an inverted photograph of it. That is the difference between a dark mode a reader keeps on and one they switch off after a paragraph.
A visitor who never turns dark mode on downloads about seven kilobytes. The engine — the part that does the real work — is fetched the moment somebody chooses dark, and never before.
A few hundred bytes go out ahead of the page and set the colours before the first paint. A reader who chose dark last time never sees a white page appear and then correct itself, which is the single thing that makes a dark mode feel bolted on.
Ink, Slate, True black, Warm, Midnight and Forest — every one of them checked for contrast before it shipped, so picking one and changing nothing gives you a page people can read. Change any of the four colours and the change is yours to keep.
Four shapes, five corners, your own wording and colours — or hide it entirely and use the block or the shortcode to place it in your header, your menu or your footer. All three ask one screen for their wording, so none of them can drift. It says what it does out loud for a screen reader either way.
Alt and a letter, never while somebody is typing. And ?dark=1 on any address opens that page dark — read before the first paint, so a link you send in the evening does not flash white on the way there.
Dark from sunset to sunrise, or between two times, worked out where the READER is rather than where your server is. Somebody in Sydney reading a shop in Berlin gets a dark page when it is dark for them.
A chart whose colours mean something, a brand badge, a video player that already has its own dark mode. Name them and they keep their own colours exactly — and a logo can be swapped for a light version outright, which is the one picture that genuinely needs it.
Two numbers a day: how many people chose dark and how many chose light. No addresses, no pages, no identifiers, no cookie of ours, and nothing leaves your own database. Off until you switch it on.
Read the theme, invert the page, or a plain stylesheet with no JavaScript at all after it loads. The screen where you choose says plainly what each one costs and what it gets wrong, so you are choosing rather than guessing.