how to add padding around header

i am using EarthlyTouch theme for a client and for some reason or another i can’t figure out how to add padding between the header and the category navigation bar. if you check out the site, you can see what i’m talking about (http://businessleadershipdevelopment.com/). i just want to add 10-20px between the two, but i can’t seem to figure it out in the editor.

i tried adding “padding-bottom: 10px;” in the theme editor-styles under “#header” and that didn’t do anything.

any advice here? thanks!