Hello Greg,

The name of that setting is "#ibox_frame", and it's in the ibox.css file.

If you use Firefox, there's a really neat add-on that will allow you to pinpoint any CSS setting right from the browser.

It's called CSS viewer, and it's available here:

https://addons.mozilla.org/en-US/firefox/addon/2104

Once it's installed, you can go to "Tools>CSS Viewer" and then everywhere you mouseover will tell you the CSS settings... it's been really helpful to me and others I've known to use CSS.

 
Let me know if there's anything else you need.