I'm completely new to css but need to get on the ball with it.
I have several websites that I work on that have mastheads & nav bars. I'd like to be able to have an external css file that describes where the masthead & nav bar elements will be placed. The current site that I'm bulding will eventually have hundreds of pages. If I make one change to the nav bar, I'll have to add it to all pages. If I have it in css, I'll only have to make the change once.