Ever wonder how the latest website designs are made? Cascading Style Sheets (CSS) are the main coding files used to lay out a website and its design. CSS 3 is the latest in styling standards, and it brings several new properties and declarations you can use to make your website design more easily created. CSS is currently the only standard in website design that plugs directly into your HTML, even the latest HTML 5 standards. With CSS 3 and HTML 5, you can create the latest interactive pages for your website viewers.