Zooming out (using the browsers page zoom i.e. cmd/ctrl -) kind of works. There is a html element <div id="zoom">-</div> on the page though but can't actually see it. I'm guessing that will zoom the page out.
That's the minus sign on the bottom right - it's for zooming the css list so that it's all in view (it was originally built to see if appended styles were more specific on a page).