Which preferences should be included?

[lukewarlow]

The current spec includes all of the MQ5 preference media queries except for forced-colors (see #15 )

This was mainly just for completeness. But questions have been raised in discussions with the CSSWG as to whether we truly need all of them, so this issue is here to discuss that.

Imo they all have valid use cases aside from potentially reducedData that one I struggle to see particularly strong use cases for.

• colorScheme speaks for itself.
• reducedMotion It's not uncommon for sites to be over the top with their animations in a way that annoys people who aren't effected bad enough to disable animation system wide. It would be nice if sites were able to honour the preference and also provide a way to reduce animation.
• contrast isn't an uncommon setting for sites to have, especially ones focussed on accessibility. Not all operating systems have an explicit setting for contrast, and all except for Windows are missing a "low" contrast preference option, because of this it's not unreasonable to assume users may not be able to set their preference correctly and this API would allow the site to step in.
• reducedTransparency like contrast this doesn't have an explicit OS setting on multiple operating systems (Android, ChromeOS and Linux) so it would be nice to give sites the option to let users control this, especially those that are focussed on accessibility.
• reducedData aside from completeness I don't see as strong a case for this option as others. Potentially useful for sites that are particularly heavy on data usage that want the option to offer a "lite" mode, even for users who otherwise don't mind data usage?

[lukewarlow]

GitHub has a number of settings that could utilise this API.

In accessibility settings they have a UI that would be replaceable with this API making use of the reducedMotion preference.

In appearance settings they have a UI for picking themes, this includes both light and dark as well as high contrast versions (along with others).

This could be partially implemented using the contrast and colorScheme preferences.

[lukewarlow]

Twitter (x) has various settings that could benefit from this API. Unfortunately they currently don't use the system values at all (afaict).

They have an accessibility settings page which could make use of prefersContrast and reducedMotion from this API.

They also have a theme setting on their display page which could use colorScheme (would need something additional for the Dim vs Lights Out dark mode)

They also have a data saver setting which could use reducedData

[lukewarlow]

Slack has two settings that could benefit from this API.

Firstly in themes they have a color mode setting which could use colorScheme

Secondly in accessibility they have an animation setting which could use reducedMotion

[lukewarlow]

Google Search could benefit from colorScheme

[lukewarlow]

Gmail's themes settings could partially make use of colorScheme and contrast

[lukewarlow]

MDN is another example of a large site that could use colorScheme.

[lukewarlow]

Popular mastodon client Elk.zone has a theme selector which matches colorScheme:

They also have an autoplay setting which could use reducedMotion and another data saving setting which could use reducedData:

[lukewarlow]

The main mastodon client has a theme selector that could use colorScheme and contrast:

They also have an animations section at least one of which could be replaced with reducedMotion