Cascading Stylesheets (CSS) is the way in which we describe the design and layout of Web pages. But is CSS a programming language, or something less than one? And have those boundaries changed over time? And what does this mean for the people creating and modifying stylesheets; what skills do they need to have? In this talk, Chris Eppstein describes what CSS has been, is, and will be, and how this will affect front-end design.