<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<!DOCTYPE bugzilla SYSTEM "https://bugs.webkit.org/page.cgi?id=bugzilla.dtd">

<bugzilla version="5.0.4.1"
          urlbase="https://bugs.webkit.org/"
          
          maintainer="admin@webkit.org"
>

    <bug>
          <bug_id>313905</bug_id>
          
          <creation_ts>2026-05-02 11:53:39 -0700</creation_ts>
          <short_desc>Text Size Boosting, text-size-adjust, and CSS Zoom</short_desc>
          <delta_ts>2026-05-02 11:53:39 -0700</delta_ts>
          <reporter_accessible>1</reporter_accessible>
          <cclist_accessible>1</cclist_accessible>
          <classification_id>1</classification_id>
          <classification>Unclassified</classification>
          <product>WebKit</product>
          <component>Text</component>
          <version>Safari 26</version>
          <rep_platform>iPhone / iPad</rep_platform>
          <op_sys>iOS 26</op_sys>
          <bug_status>NEW</bug_status>
          <resolution></resolution>
          
          
          <bug_file_loc></bug_file_loc>
          <status_whiteboard></status_whiteboard>
          <keywords></keywords>
          <priority>P2</priority>
          <bug_severity>Normal</bug_severity>
          <target_milestone>---</target_milestone>
          
          
          <everconfirmed>1</everconfirmed>
          <reporter>John.W.Jones89</reporter>
          <assigned_to name="Nobody">webkit-unassigned</assigned_to>
          <cc>fantasai.bugs</cc>
    
    <cc>vitor.roriz</cc>
          

      

      

      

          <comment_sort_order>oldest_to_newest</comment_sort_order>  
          <long_desc isprivate="0" >
    <commentid>2206903</commentid>
    <comment_count>0</comment_count>
    <who name="">John.W.Jones89</who>
    <bug_when>2026-05-02 11:53:39 -0700</bug_when>
    <thetext>I see there are some other issues reported with iOS and iPadOS around CSS Zoom and the automatically applied &quot;text boosting&quot; or counter-scaling, though I&apos;m not sure they hit the mark for my issue with it, apologies if this is a duplicate.

I contribute to an app that generates previews of pages that are made of containers of text.  The preview area has a zoom slider, which is applied to the whole preview area to grow/shrink the pages.  

Unfortunately, the auto counter-scaling of font-sizing means that as the pages shrink the text inside them does not (at a certain point), and then overflow the pages.  It&apos;s a pretty big blocker in terms of adapting the site to mobile.  Though I&apos;ve recently realized this isn&apos;t a problem on Android.

The web app that I&apos;m talking about: https://homebrewery.naturalcrit.com/share/N3AnOcvN6G8a

A blog post I&apos;ve written with some additional screenshots/context: https://longjohnjones.com/homebrewery/article/ios-css-zoom-and-text-scaling/

A CodePen for testing it out (though this likely just affirms the designed behavior-- and I think this is where my report differs from others (I think?).  Where I feel that other reports are about bugs, I think what I&apos;m raising an issue with the idea of mandatory text scaling?  I&apos;d love to be told I&apos;m just holding `text-size-adjust` wrong and can easily override the size scaling at small sizes.

https://codepen.io/editor/Gazook89/pen/019de916-0d86-73c0-94ab-f0bb0302c1dd

Thanks for your time</thetext>
  </long_desc>
      
      

    </bug>

</bugzilla>