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    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - font-size measured in ex or ch scales quadratically with page zoom"
   href="https://bugs.webkit.org/show_bug.cgi?id=159617">159617</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>font-size measured in ex or ch scales quadratically with page zoom
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>WebKit
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>Safari 9
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>Unspecified
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Unspecified
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>Normal
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P2
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>Layout and Rendering
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>webkit-unassigned&#64;lists.webkit.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>peter.krautzberger&#64;mathjax.org
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>simon.fraser&#64;apple.com
          </td>
        </tr></table>
      <p>
        <div>
        <pre>WebKit's behavior seems identical to <a href="https://bugs.chromium.org/p/chromium/issues/detail?id=408777">https://bugs.chromium.org/p/chromium/issues/detail?id=408777</a>. 

Copied from there:

<span class="quote">&gt; Example URL:
&gt; <a href="http://web.mit.edu/andersk/Public/font-size-css-units.html">http://web.mit.edu/andersk/Public/font-size-css-units.html</a>
&gt; 
&gt; Steps to reproduce the problem:
&gt; 1. Visit <a href="http://web.mit.edu/andersk/Public/font-size-css-units.html">http://web.mit.edu/andersk/Public/font-size-css-units.html</a>
&gt; 2. At 100% page zoom, observe that all the lines are roughly the same size.
&gt; 3. Zoom in.
&gt; 
&gt; What is the expected behavior?
&gt; All lines should get bigger by the same ratio.
&gt; 
&gt; What went wrong?
&gt; The lines where font-size is measured in ex or ch get bigger much faster than the other lines.  At 500% page zoom, they are shown at 25 times their original size.
&gt; 
&gt; Does it occur on multiple sites: Yes
&gt; 
&gt; Does this work in other browsers? Yes</span >

While Blink is also affected, Firefox and IE/Edge are not.

Thanks in advance for looking into it!</pre>
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