I thought that the search area on the top of each page was a bit bland and I set out to style it. The whole search area is enclosed in an id, WebPartWPQ1. I added this id to my theme css and gave the area some padding and margins, and I added a background. To change the color of the background of the magnifying glass, I copied the td.ms-sbgo class from core and changed the background color. Is nice, yes?