How do I change the admin header color in Magento?

I'm re-skinning Magento's admin dashboard. How do I change the color of the top nav (the portion that is behind the logo)? I assume this is a CSS change 开发者_StackOverflow中文版but I can't seem to find the line of code to change this.

Try line 527 in DOCROOT\skin\adminhtml\default\default\boxes.css

.header { background:url(images/header_top_bg.gif) repeat-x #425e66; text-align:right; }

The colour is mostly coming from the background image.

JD