Hi. How do I change the background color of the auto-nav in Greek Yogurt theme? No matter what color I specify in "Design" it is always the header background color that is displayed. I want the two to be different.

Do I need to do a custom template? If so, how do I do that? (I would be grateful for step-by-step instructions as I am a novice at this).

Or do I need to edit some css code? If so, where? Again I would be grateful for specifics to help me.

Thanks!