I'd like to change the size of the text in the header of the default theme. I have a very basic understanding of CSS. I went to the "header template" pane in the Theme Editor section of WP, and saw (I think) that the name of the title class is "header" and the name of the description class is "description". Then I went over to the "stylesheet" pane and changed the text sizes for each of these classes. When I viewed the site, and refreshed, no change at all. What am I doing wrong?