background color of portal favourites

Hi Experts,

I have to change the background color of standard portal favourites iview from blue to white.

I have also tried editing the content.css file of the KM content.But it is not reflecting in the iview.

I have also changed some options in themes like iview trays,Portal body,screen areas of applications background color to white.No luck.

Please guide me with a successful strategy.

Thanks

Deepak