Learning by Hacking

Background

This document defines formatting and style rules for HTML and CSS. It aims at improving collaboration, code quality, and enabling supporting infrastructure. It applies to raw, working files that use HTML and CSS, including GSS files. Tools are free to obfuscate, minify, and compile as long as the general code quality is maintained.

HTML4 and CSS2 currently support media-dependent style sheets tailored for different media types. For example, a document may use sans-serif fonts when displayed on a screen and serif fonts when printed. ‘screen’ and ‘print’ are two media types that have been defined. Media queries extend the functionality of media types by allowing more precise labeling of style sheets.

A media query consists of a media type and zero or more expressions that check for the conditions of particular media features. Among the media features that can be used in media queries are ‘width’, ‘height’, and ‘color’. By using media queries, presentations can be tailored to a specific range of output devices without changing the content itself.