title: Is it possible to apply css only to a window opened by an extension?
body: <p>Basically I have this in my background.js:</p>
  <pre><code>chrome.browserAction.onClicked.addListener(function(tab) {
      wnd = window.wnd &amp;&amp; window.wnd.close() || window.open(&quot;https://mail.google.com/&quot;, &quot;_blank&quot;, &quot;toolbar=yes,scrollbars=yes,resizable=no,top=50,left=50,width=1000,height=800&quot;);
  });
  </code></pre>
  <p>which opens a gmail window.</p>
  <p>I know I can style it with</p>
  <pre><code>&quot;matches&quot;: [&quot;https://mail.google.com/*&quot;]
  </code></pre>
  <p>But then my style.css applies to all windows with gmail in them, is it possible to apply css only to the window opened by the extension?</p>