I have been trying to reduce the height of the #nav menu bar on the Enterprise theme. Originally, it is set at 45px. I have changed the height to 30px, but the black background’s height does not get smaller.
You have set a “minimum” height. That means it will not get shorter than that number. Because a “min-height” is set in the original CSS, set a max-height as well and make them both the same. (I tried setting a regular height, but the min-height overrides it no matter what.)
You will also have to set a line height in #supernav ul otherwise the current page background image will hang out the bottom. 5px seems to work with a height of 30px.