Inverted colors

Inversion is the bluntest accessibility setting an operating system ships. Every pixel on the way to the display is flipped, which turns a white page into a black one at zero cost to the OS and with no cooperation from anything running on it. People use it to cut glare, to read in bed, to make low vision text stand out, and often because their platform got there years before individual apps had a dark theme of any kind.

Because it is a transform rather than a palette, the results are unlike either of its neighbours. Dark mode is a second set of colours you designed and tested, so a dark surface stays a surface. Forced colours mode throws your palette away and substitutes the user’s own small set, so you lose control but keep semantics. Inversion keeps your palette and negates it, which means every relationship you built survives and every absolute value is wrong. Photographs become negatives. Brand colour lands somewhere nobody chose. A shadow is dark paint, so it comes back as a bright halo, and the card that was floating above the page now looks lit from underneath.

Apple splits the setting in two for exactly this reason. Classic Invert flips everything, media included. Smart Invert tries to hold back images, video and interface that is already dark, which fixes the photograph problem most of the time and is heuristic all of the time: it reads the rendered result, so a photo drawn as a CSS background, or an icon shipped as a bitmap, can be left inverted while the picture beside it is spared. Nothing about your markup is consulted, and there is no attribute that opts an element out.

The design job is therefore small and mostly about restraint. Do not detect and defeat it: the inverted-colors media feature exists, is barely supported, and reinverting your own page fights a user who asked for this. Instead draw elevation with something other than a dark blur where it matters, keep meaning off single absolute colours (see use of color), ship real images as <img> rather than as backgrounds so Smart Invert can recognise them, and check a screen or two under both invert modes the way you would check a dark theme. It takes a minute and it is the only way you will see the halo.