High Contrast Current landscape of OS color modes and contrast features Dark mode Inverted colors High contrast text (experimental) Increase contrast High contrast (web extension) Windows High Contrast Windows High Contrast demo Comparison to related features Related OS/extension feature comparison

Dark Mode Inverted Text Contrast Increase High Contrast High Contrast Colors Contrast extension Supported MacOS, Windows iOS, Android, Android MacOS, iOS Chrome Windows Platform Windows (experimental) Contrast Should meet min No promise High for text but Intermediate Varies by Guaranteed “promise” WCAG dependent on theme and based on user requirements background web content choice Applies to UI, app content UI, app UI, app content UI, app Web content UI, app/web content content content Modifiable No No No No (legacy No (outside of Yes, limited by users modifiable) theme color theme selection) Forced to No Yes No No Yes Yes web content Modifiable Yes* No No Yes* No Yes by authors Related CSS features comparison

prefers-color-scheme prefers-contrast inverted-colors high-contrast Related MacOS and Windows MacOS/iOS increase iOS, Android, Windows high browser/OS light/dark mode contrast; Android text Windows color contrast features contrast? inversion Granularity of No preference, light, No preference, low, high On/off On/off; additionally, detection in web dark (increased keyword?) detection of preset content themes Expectations on Author styles theme; Self-authored styles; Honors user Honors user author hints as to supported authors need guidance preference first; preference first; schemes on handling ratios author can adjust author can adjust Additional info None None None Abstracted system available to author colors based on user- set preferences Implementations Webkit; Gecko in None Webkit Trident, EdgeHTML progress; Blink i2i Proposal: let authors target the High Contrast feature itself Most closely related in concept to inverted-colors

Considers user preference as highest directive

Forced on web content

Built expressly with accessibility in mind

Many use cases work out of the box; author involvement expected to be minimal/tweaks High usage

4% of active Windows machines

This makes High Contrast by far the most popular in- box assistive technology on the Windows platform Consistent developer story

Easier to maintain existing styles for IE and new High Contrast styles for modern Windows browsers (and any other similar future implementations) when authoring story is consistent with familiar approach high-contrast MQ explainer