Introduction to CSS


About this Document


  This document is Copyright (c) Information Technology Group,
  www.itgroup.ro, Alin Avasilcutei, Cornel Paslariu, Virgil Mager.

  Permission is granted to copy, distribute and/or modify this document
  under the terms of the GNU Free Documentation License, Version 1.2
  with no Invariant Sections, no Front-Cover Texts, no Back-Cover Texts.

This document is an introduction to the Cascaded Style Sheets (CSS) technology. As CSS is not fully mature at the time of writing this document, a number of differences between standards' recommendations and the available implementations on various browsers exist; however, most of the CSS functionality presented in this document is available on the major browsers on the market.

The reader of this document is assumbed familiar with:

What is a CSS Style

The Cascaded Style Sheets (CSS) technology was developed with the purpose of drawing a separation between the way the information inside an HTML document is "presented" on one hand, and the information itself on the other. Specifically, the notion of 'presentation style', or 'CSS Style', has been introduced, such that the way in which each element inside a document is rendered can be customized by means of several 'style parameters'. For example, by designing an appropriate CSS Style, almost any type of HTML element can be displayed surounded by a rectangular border with a specified color and width (the color and width of the border will be part of the style specification).
The following paragraphs introduce the mechanism, and general syntax, by which a presentation style can be defined and attached to one or more HTML elements.