Maybe you're happy with the template as it is now that you've personalized the logo and tagline text. However, in many cases, you may want to customize the design even more. To do this, you have to edit the CSS files of the template. Cascading Style Sheets (CSS) define the design of the site—the HTML code provides the basic structure of the page. It is used to customize the layout, color, and typography. We'll come back to the principles of CSS soon, but the best way to find out how it works is to play around with it a little. As an example, we'll change the style of the tagline text. Right now, it's pretty small and inconspicuous, so let's make it bigger and bolder.