PSD to Code: Build the CSS – Header Now that you have the skeleton created and your images prepared, it is time to make those pieces fit using CSS to style your site. First up in the CSS process is Chapter 5a: Build the CSS - Header. To complete the Mission work through the tutorial and take a couple screenshots as evidence of what you learned. Mastery is simple, Visitor. You just need to post what you learned on your SITREP.