On Fri, Apr 10, 2026 at 11:06 PM 'Alexander Kyereboah' via blink-dev <
[email protected]> wrote:

> *Contact emails*
> [email protected], [email protected], [email protected],
> [email protected], [email protected]
>
> *Specification*
> https://www.w3.org/TR/css-color-4/#css-system-colors
>
> *Summary*
> The `AccentColor` and `AccentColorText` system colors can be used in CSS
> to access the system accent color specified on the user's device. This
> allows developers to apply native app like styling to their web content in
> contexts where users expect OS theme integration, such as an installed web
> application.
>
> *Blink component*
> Blink>CSS
> <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3ECSS%22>
>
> *Web Feature ID*
> system-color <https://webstatus.dev/features/system-color>
>
> *Motivation*
> Without access to system accent colors, developers must hardcode theme
> values or implement non‑native design patterns, resulting in web
> applications that visually diverge from user‑configured platform settings.
> This is especially noticeable in installed web apps, where users expect a
> level of OS‑level visual integration comparable to native applications.
>
> *Initial public proposal*
> *No information provided*
>
> *TAG review*
> No architectural changes to make, `AccentColor` and `AccentColorText` are
> standardized and fully spec'ed CSS keywords.
>
> *TAG review status*
> Not applicable
>
> *Risks*
>
> *Interoperability and Compatibility*
> This has no interop or compat risks because it is a new CSS system color.
>

"Interop risk" means "are other implementers likely to also ship this?".
>From the positions below, it doesn't seem like there's no risk.


>
> *Gecko*: Shipped/Shipping (
> https://bugzilla.mozilla.org/show_bug.cgi?id=1775247)
>
Are they already shipping the exact same behavior we want to ship?

>
> *WebKit*: No signal (
> https://github.com/WebKit/standards-positions/issues/136)
>
The discussion on that thread is a bit more subtle than "no signal". Can
you maybe summarize it here?


> WebKit Bug: https://bugs.webkit.org/show_bug.cgi?id=241866
>
> *Web developers*: Positive (
> https://issues.chromium.org/issues/40229450?pli=1)
> There are at least 25 upvotes on the Chromium issue tracking this bug,
> showing wider interest in the feature.
>
> *Ergonomics*
> `accent-color: auto` also exposes the system accent color via styled form
> controls. Unlike `AccentColor/AccentColorText`, it was originally unscoped,
> leading to inconsistent availability of system color styling. We have since
> aligned behavior by scoping system colors to web app and initial profile
> contexts, scheduled for Chrome 149. `AccentColor/AccentColorText` is
> planned for Chrome 150 to allow buffer time in case compat issues with the
> scoping change need rollback.
>
> *Activation*
> It will not be challenging for developers to take advantage of this
> feature as-is. This feature would not benefit from polyfills.
>
> *Security*
> This feature could be used for fingerprinting by exposing the user's
> system accent color to the web. To mitigate this, we've scoped access to
> the system accent color to only installed web app contexts to narrow the
> breadth of exposure and additionally made it only accessible to the
> primary/initial profile to prevent cross-profile fingerprinting scenarios.
>
> *WebView application risks*
>
> Does this intent deprecate or change behavior of existing APIs, such that
> it has potentially high risk for Android WebView-based applications?
> No risk.
>
>
> *Debuggability*
> These new system colors should automatically be picked up by DevTools'
> styles sidebar for autocomplete/validity.
>
> *Will this feature be supported on all six Blink platforms (Windows, Mac,
> Linux, ChromeOS, Android, and Android WebView)?*
> No
> `accent-color` does not use the system accent color on Android. With
> Android automatically sampling system accent colors from the user's
> wallpaper, there is a security/privacy risk in enabling on Android.
>
> *Is this feature fully tested by web-platform-tests
> <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md>?*
> Yes
> While we can't fully test the properties end to end due to the requirement
> of OS interaction, we have WPTs testing system color validity and automated
> testing for proper availability scoping.
> WPT:
> https://wpt.fyi/results/css/css-color/parsing/color-valid-system-color.html?label=master&label=experimental&aligned&q=color-valid-system-color.html
>
> Automated browser tests:
> https://source.chromium.org/chromium/chromium/src/+/main:content/browser/accent_color_browsertest.cc
>
> *Flag name on about://flags*
> CSSSystemAccentColorKeyword
>
> *Finch feature name*
> CSSSystemAccentColorKeyword
>
> *Rollout plan*
> Will ship enabled for all users
>
> *Requires code in //chrome?*
> False
>
> *Tracking bug*
> https://issues.chromium.org/issues/40229450?pli=1
>
> *Estimated milestones*
>
> Shipping on desktop
> 150
> DevTrial on desktop
> 115
> DevTrial on Android
> 115
>
> *Anticipated spec changes*
>
> Open questions about a feature may be a source of future web compat or
> interop issues. Please list open issues (e.g. links to known github issues
> in the project for the feature specification) whose resolution may
> introduce web compat/interop risk (e.g., changing to naming or structure of
> the API in a non-backward-compatible way).
> CSSWG issue https://github.com/w3c/csswg-drafts/issues/10372 tracks
> ongoing discussion regarding privacy mitigations for exposing user‑specific
> system colors such as `AccentColor` and `AccentColorText`, as no single
> cross‑UA fingerprinting mitigation approach has yet been standardized.
> Chromium has implemented context‑based exposure mitigations (e.g. limiting
> access to installed web app environments) that have undergone internal
> privacy review and operate within the existing CSS Color specification
> semantics. While future WG consensus on a unified mitigation model may
> introduce clarifications around when system color values are exposed, we do
> not anticipate any API shape changes or other spec resolutions that would
> introduce meaningful web compatibility or interoperability risk relative to
> current implementations.
>
> *Link to entry on the Chrome Platform Status*
> https://chromestatus.com/feature/5068127364186112?gate=5105472708804608
>
>
> This intent message was generated by Chrome Platform Status
> <https://chromestatus.com/>.
>
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>

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