Re: [csswg-drafts] [css-fonts-5] <meta text-scale> limits (#13557)

I just want to share again [the investigation on how browsers currently let users scale content](https://github.com/w3c/csswg-drafts/blob/main/css-env-1/explainers/env-preferred-text-scale.md#existing-user-controls-to-scale-content) that @davidsgrogan and I did as part of the `env(preferred-text-scale)` explainer in case it's helpful.

Also PaulG, here is the [Explainer for the meta text-scale tag.](https://github.com/w3c/csswg-drafts/blob/main/css-env-1/explainers/meta-text-scale.md)

In summary, right now without the `<meta text-scale>` tag:

- On desktop:
  - At the OS/platform level:
    - macOS: No browser respects the OS-level text scale setting
    - Windows: Chromium-browsers and Firefox set the zoom equivalent to the OS text scale setting, rather than increasing the text scale (e.g. if the user increases their text scale by 150%, the browsers zoom web pages by 150% rather than increase the text scale)
  - At the UA level:
    - on all OSs: Chromium-based browsers and Firefox let the user change the value of `font-size: medium` in the browser settings. Firefox also allows per-domain text scaling by enabling the 'zoom text only' setting.
    - macOS: Safari allows per-domain text scaling with a keyboard shortcut
- On mobile:
  - At the OS/platform level:
    - iOS: No browser respects the OS-level text scale setting
    - Android: No Chromium-based browsers respect the OS-level text scale setting. Firefox set the zoom equivalent to the OS text scale setting, rather than increasing the text.
  - At the UA level:
    - on all OSs: There are no settings to change the text scale

(I could probably turn this into a table.)

So currently, the way text scale is handled greatly varies. The intent behind the `<meta text-scale>` tag was to unify all UAs on all OSs so that they do the same thing when the tag is present: simply scale the `font-size: medium` based on the user's OS setting and UA setting (if there is a UA setting).

I wanted to bring this up because I'm not sure if the variations in how it works between platforms and browsers is confusing our understanding of this issue of whether the author should be able to set a scaling limit (and whether a scaling limit would cause a regression on desktop).

(I'm on holiday/vacation for the rest of the week, but I'll try and catch up with @fantasai before the meeting next Wednesday.)

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Received on Thursday, 16 April 2026 00:04:54 UTC