Thank you for the excellent explainer. It's a shame this behavior can't be the default, but due to compat an opt-in makes sense. LGTM1.
On Thursday, January 15, 2026 at 4:48:26 PM UTC-8 Chromestatus wrote: > *Contact emails* > [email protected], [email protected] > > *Explainer* > > https://github.com/w3c/csswg-drafts/blob/main/css-env-1/explainers/meta-text-scale.md > > *Specification* > https://drafts.csswg.org/css-fonts-5/#text-scale-meta > > *Summary* > Makes the root element's default font size scale in proportion to both the > operating system's and browser's text scale setting. This allows pages that > follow best practices around font-relative units (i.e. use rem and em for > font sizes and page elements that should change with the user's text size > preferences) to respect the user's OS-level text scale setting. This also > causes the browser to disable existing browser-based mechanisms (i.e. > full-page zoom on windows) and heuristics (i.e. text autosizing on mobile). > Now web developers can signal to the browser that the page is constructed > in a way (i.e. with rem and em) that will scale well across various > user-selected font size preferences. Similar to env(preferred-text-scale), > which provides authors with a way to access the text scale; this API > extends that by enabling scaling via the root element's default font size > and opting-out of automatic text scaling. > > *Blink component* > Blink>Accessibility > <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3EAccessibility%22> > > *Web Feature ID* > Missing feature > > *Motivation* > Authors currently don't have an easy way to respect the OS-level text > scale setting on all devices. It is practically impossible to detect and > respect this on desktop. On mobile, there is env(preferred-text-scale), but > authors would need to use it in calc() functions to set the root font-size > and some media queries. They would need a lot of guidance to ensure it gets > used correctly and there would be little variation in how they would use > it. Therefore, it would be much easier for authors if they could continue > to use font-relative units as they do now and the UA initial font-size was > redefined to incorporate the OS-level text scale setting. > > *Initial public proposal* > https://github.com/w3c/csswg-drafts/issues/12380 > > *TAG review* > https://github.com/w3ctag/design-reviews/issues/1172 > > *TAG review status* > Issues addressed > > *Risks* > > > *Interoperability and Compatibility* > Compat – no issues as it's a new feature Interop – none really – even if > other browsers don't implement it's a progressive enhancement > > *Gecko*: No signal ( > https://github.com/mozilla/standards-positions/issues/1326) > > *WebKit*: No signal ( > https://github.com/WebKit/standards-positions/issues/587) > > *Web developers*: Positive ( > https://github.com/w3c/csswg-drafts/issues/12380) Positive emoji votes on > the initial proposal > > *Other signals*: > > *Activation* > We intend to do some outreach after the feature has baked on Stable. Some > ideas are discussed at the end of this TAG review comment: > https://github.com/w3ctag/design-reviews/issues/1172#issuecomment-3667481287 > > *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 higher risk. This opt-in feature has WebView-specific behaviors. The > goal of the WebView-specific parts is to allow authors to ensure their > pages render identically on Chrome and WebView. Today renderings may not be > identical due to some WebView font-sizing quirks. See commit message at > https://chromium-review.googlesource.com/c/chromium/src/+/7280046 for > more info. > > > *Debuggability* > *No information provided* > > *Will this feature be supported on all six Blink platforms (Windows, Mac, > Linux, ChromeOS, Android, and Android WebView)?* > Yes > > *Is this feature fully tested by web-platform-tests > <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md>?* > No > Not tested in WPT because there is no API to simulate changing user font > size preferences. The wpt_internal tests are at > https://source.chromium.org/search?q=file:meta&sq=&ss=chromium%2Fchromium%2Fsrc:third_party%2Fblink%2Fweb_tests%2Fwpt_internal%2Fcss%2Fcss-fonts%2F > > There are other automated WebView java tests and C++ Unit tests. > > *Flag name on about://flags* > *No information provided* > > *Finch feature name* > TextScaleMetaTag > > *Rollout plan* > Will ship enabled for all users > > *Requires code in //chrome?* > False > > *Tracking bug* > https://crbug.com/430566925 > > *Measurement* > Added WebDX UseCounter in > https://chromium-review.googlesource.com/c/chromium/src/+/7267330 > > *Estimated milestones* > Shipping on desktop 146 > Shipping on Android 146 > Shipping on WebView 146 > > *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). > *No information provided* > > *Link to entry on the Chrome Platform Status* > https://chromestatus.com/feature/5112244702674944?gate=5080483318857728 > > *Links to previous Intent discussions* > Intent to Prototype: > https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOZbSt0S4JY2pHY23SVKTFR63Q3ak5Z8RXmqqNhHkXigb2feKw%40mail.gmail.com > > > This intent message was generated by Chrome Platform Status > <https://chromestatus.com>. > -- You received this message because you are subscribed to the Google Groups "blink-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. 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