LGTM2
/Daniel
On 2026-04-15 17:32, Rick Byers wrote:
In the API owners meeting today we discussed this at some length.
There was some concern that the lack of predictability here could
cause an adoption barrier for web developers, but also a general
agreement that this concern doesn't rise to the level of blocking
shipping. From my perspective this is not fundamentally as bad as the
unpredictability that comes from font matching / metrics depending on
system (and sometimes user) settings.
LGTM1
On Mon, Apr 13, 2026 at 2:16 PM 'Alexander Kyereboah' via blink-dev
<[email protected]> wrote:
/> "Interop risk" means "are other implementers likely to also
ship this?". From the positions below, it doesn't seem like
there's no risk./
Thanks for the clarification. Both Gecko and WebKit already
implement these keywords to some degree today. Gecko exposes the
underlying system accent color in most contexts, and WebKit
currently returns a constant value rather than the user’s system
color. However, discussion on the WebKit position thread indicates
interest in a solution that would return the actual system accent
color. This signals alignment on the capability itself, with
ongoing discussion primarily focused on mitigating risk rather
than whether to support it at all.
/> //Are they (Gecko) already shipping the exact same behavior we
want to ship? /
Not exactly, but there is meaningful implementation overlap. Gecko
already exposes the underlying system accent color via existing
system color keywords on most platforms when the relevant pref is
true (currently all platforms except Windows).
`AccentColor/AccentColorText` was enabled wherever that
infrastructure was already present. While their exposure model is
a bit looser than what we have, the end result is that Gecko does
already ship system accent color exposure in supported
configurations. System color exposure being scoped to installed
web apps and initial profiles are additional privacy mitigations
for us on top of that baseline behavior.
/> Thediscussion on that thread is a bit more subtle than "no
signal". Can you maybe summarize it here?/
WebKit expressed interest in supporting these keywords in order to
better align web UI with platform theming, but they also noted
that implementation would likely depend on identifying an
acceptable privacy mitigation for exposing user‑specific accent
colors, and discussion has focused on how to do so safely rather
than whether the capability itself is desirable. With no consensus
being reached yet, currently tracking it as "No Signal".
On Sunday, April 12, 2026 at 10:48:22 PM UTC-7
[email protected] wrote:
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
<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
<https://chromestatus.com/feature/5068127364186112?gate=5105472708804608>
This intent message was generated by Chrome Platform
Status <https://chromestatus.com/>.
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