This area of the site code is a bit tricky. Sure you have the standard CSS that goes with it. First there’s no default height or width in the header and the generic height is dependant on the page title – tagline.

#header {}
	#header h1 a {}
	#header .description {}

If the Plugin Wonderful plugin is active and you set one of your ads as ‘header’ then it will open up another CSS element.

	#header .headerpwad {}

Also if you decide to put anything into the Header sidebar area it will open up another css element inside of #header. Which doesn’t have any default styling.

#sidebar-header {}