How can I overwrite the default Google CSE CSS/styles?

How can I overwrite the default Google CSE CSS/styles?

On a site I am working on, there is a google CSE box being displayed from an iFrame. I do not have direct access to the child page inside the iFrame. The links in the iFrame do not match my site, and I was hoping there was a way to overwrite the styles, changing the link colors and text size.

Do you know of a way that I can do this, using CSS and/or Javascript (or any method other than these would be good too). If you include any code, please tell me in which document, and where in that document, the code needs to be placed, and which variables (element ids, classed, etc) need to be swapped out.

If you *know* of a website that explains how to do this, even a link or a point in the right direction would be greatly appreciated. I don't need links to the first pages you find when you search for it on the web, I've already done that myself.