Cascading Style Sheets or CSS define the look and feel of the web as we know it. While HTML and JavaScript focus on the functional side of the web, CSS deals with the visual aspects of it.Need help navigating the world that is CSS3? Download our "Essential CSS3 Properties Cheat Sheet" today! After you’ve learned how to build static webpages with HTML, it’s time to discover how to style them and make them presentable with CSS.