WARNING – Geek Speak Ahead!
HTML is the standard programming language for describing the contents and appearance of Web pages. HTML 5 is the next revision that will allow the Web browser to become a development platform. A primary goal for HTML 5 is to ensure interoperability among browsers so that Web applications and documents behave the same way no matter which HTML 5-compliant browser is used to access them.
CSS controls the design of your website. CSS3 is the latest version of CSS and it’s designed to work with HTML5.