HTML is a markup language for structuring and presenting content for the World Wide Web. HTML5 is the latest version for HTML presenting an improvement in markup elements for regular websites and mobile. HTML5 is also a potential candidate for cross-platform mobile applications. Many features of HTML5 have been built with the consideration of being able to run on low-powered devices such as smartphones and tablets.
CSS is used to control the style and layout of Web pages. CSS3 is the latest standard for CSS and is split up into "modules". Each module adds new capabilities or extends features defined in CSS 2, over preserving backward compatibility.
Since version 2.0 it also supports responsive design. This means the graphic design of web pages adjusts dynamically, taking into account the characteristics of the device used (PC, tablet, mobile phone).
Responsive Web Design is an approach to web design in which a site is crafted to provide an optimal viewing experience—easy reading and navigation with a minimum of resizing, panning, and scrolling—across a wide range of devices (from desktop computer monitors to mobile phones).