Framed Editor body colour

Hi, I'm new to CKEditor and I have been trying to add some jQuery to change the background colour of the editable content when it comes into focus.

I was working on the idea that something like:

$('someselector').focus(function() {
        $(this).css({backgroundColor: "#FFDDAA"});
 });

Am I on the right track? If so, which selector do I need to use?

Terry