Nocturne Dark Mode

Most dark mode add-ons do one thing to every page. They take every colour on it and flip it. You get a dark page out of that, along with inverted photos, logos that look like negatives, and the site's own dark theme thrown away in the process.

Nocturne looks for that theme first.

Plenty of sites already support dark mode. They're just waiting for you to dig a toggle out of a settings menu, or for your whole operating system to switch over. Nocturne finds the switch and flips it for you. What you're looking at then isn't a guess at how the site might look dark; it's the dark theme its own designers built, exactly as they built it.

When a site really has none, Nocturne builds one. Then it looks at the page it just made and measures whether the thing actually came out dark and readable. If it didn't, that attempt gets thrown away and a different approach gets tried. Nothing is applied on the assumption that it worked. The toolbar popup tells you which of the two happened, so when a site looks especially good (or especially rough) you know why.

WHAT YOU GET

No white flash. Open a link at night and the dark page is what arrives, not half a second of blinding white first. The part that handles this is plain CSS with no script behind it, because anything waiting on JavaScript is already too late.

Photos stay photos. Images, video and logos are never inverted. Want them a little softer at night? There's a dimming slider, and dimming is all it does.

Text you can actually read. Every piece of text is checked against whatever is behind it and lightened or darkened until it clears a contrast ratio you set.

Colours keep their identity. A yellow warning stays yellow. A brand blue stays that blue instead of going muddy or radioactive.

It's quick. Six thousand elements on a page, finished in about half a second, using eleven rules to do it.

It knows when to stop. A page that's already dark gets left completely alone, because re-theming something a designer already built for the dark is the fastest way there is to ruin it.

CONTROLS

Five palettes, from a soft deep blue through neutral grey to a high contrast option. Sliders for brightness, contrast and colour intensity, plus a minimum contrast setting. Per-site settings for all of it.

Disagree with what Nocturne picked? There are four methods you can pin instead. Only want it after dark? Run it always, only while your system is in dark mode, or between hours you choose. There are keyboard shortcuts for switching it off on one site and for switching it off everywhere.

PRIVACY

Nocturne makes no network requests. Not in any mode, not ever. There's no analytics and no account. Nothing is downloaded from anywhere, and no server is involved at any point. Everything it needs ships inside the add-on itself, so there's no fix list to fetch and no update channel to phone home to, and your settings stay in your browser.

That part is checked, not just promised. The build refuses to produce a package if any networking code shows up anywhere in the source. Would you rather see for yourself than take that on trust? The whole project is open source, with nothing minified and nothing obfuscated, so you can run that check yourself.

It asks for no site access when you install it.

WHAT IT CANNOT DO

Being straight about this seems more useful than the alternative.

Apps that draw to a canvas are pixels rather than text and colours, which covers some document editors, most spreadsheets and plenty of map tools. There's nothing in there to recolour.

A few sites build their interface in a way that seals it off from every add-on, not only this one. Those parts stay light.

Some sites hide part of their styling from add-ons entirely. Nocturne notices when that's left a page half done and switches to a method that works instead.

Firefox blocks add-ons on its own restricted domains, such as addons.mozilla.org and accounts.firefox.com, so pages there stay light.

Your browser's own interface can still flash. That's Firefox painting, not the page.

Free and open source, MIT licensed. Source, technical notes and the full test suite: https://github.com/TiltedLunar123/nocturne