I've built a very simple jQuery overlay which works fine in non-Microsoft browsers. I now want to debug the CSS for the overlay so that it works in IE 8 Comptability View and Quirks Mode.

The overlay can be seen at <http://pointlessandannoying.com/so/> - click the 'about' link in the bottom right of the page to display the overlay. Could anyone suggest a good place to start with regards to the debugging?