there has been lots of confusion about iframe and background color etc.
here is the myth iframe color cannot be changed if you have css run from a default file like default.css
here is the solution:
paste the following in your default css file. i pasted mine at the end of everything and it worked fine.
note this is just to change the color to white. I have not tested but believe that any modifications to iframe properties can be modified here and will change any and all iframes that do not have prepending rules like websites that look normal inside an iframe.
[edited by: incrediBILL at 1:19 am (utc) on May 11, 2010]
[edit reason] removed personal URLs, see TOS #13 [/edit]