<p>Here is a reasonable work-around on FireFox:</p>
<ol>
<li><p>Install <a href="https://addons.mozilla.org/en-US/firefox/addon/styl-us/?utm_source=addons.mozilla.org&amp;utm_medium=referral&amp;utm_content=search" rel="nofollow noreferrer">Stylus</a>.</p>
</li>
<li><p>Click Stylus' badge in the tool bar, and select Manage.</p>
</li>
<li><p>Select Write new style, and paste the below into it (edit as needed, e.g., add <code>domain(&quot;askubuntu.com&quot;),</code>):</p>
</li>
</ol>
<p>
<pre><code>/* ==userstyle==
@name Stack Exchange
@namespace Steven Penny
@version 1.0.0
==/userstyle== */
@-moz-document
domain(&quot;stackexchange.com&quot;),
domain(&quot;stackoverflow.com&quot;),
domain(&quot;superuser.com&quot;) {
   body {
      --ff-sans: Arial;
   }
   .topbar-dialog .modal-content .message-text h4,
   .topbar-dialog,
   header {
      font-family: var(--ff-sans) !important;
   }
   .full-diff .content,
   .wmd-input,
   code {
      font-family: Consolas !important;
   }
}
</code></pre>
<ol start="4">
<li><p>Click Save.</p>
</li>
<li><p>Close the Stylus&gt;Manage window, and breathe a sigh of relief.</p>
</li>
</ol>
