Cascading Sheet Style

Cascading Style Sheets (CSS) is a style sheet language used for describing the look and formatting of a document written in amarkup language. While most often used to style web pages and interfaces written in HTML and XHTML, the language can be applied to any kind of XML document, including plain XML, SVG and XUL.

CSS is designed primarily to enable the separation of document content from document presentation, including elements such as thelayout, colors, and fonts. This separation can improve content accessibility, provide more flexibility and control in the specification of presentation characteristics, enable multiple pages to share formatting, and reduce complexity and repetition in the structural content (such as by allowing for tableless web design).

CSS specifies a priority scheme to determine which style rules apply if more than one rule matches against a particular element. In this so-called cascade, priorities or weights are calculated and assigned to rules, so that the results are predictable.

The CSS specifications are maintained by the World Wide Web Consortium (W3C). Internet media type (MIME type) text/css is registered for use with CSS by RFC 2318 (March 1998), and they also operate a free CSS validation service.^[2

codes

For example, under pre-CSS HTML, a header element defined with red text would be written as:

<h1><font color="red"> Chapter 1. </font></h1>

Using CSS, the same element can be coded using style properties instead of HTML presentational attributes:

<h1 style="color:red"> Chapter 1. </h1>

An "external" CSS file, as described below, can be associated with an HTML document using the following syntax:

<link href="path/to/file.css" rel="stylesheet">

An internal CSS code can be typed in the head section of the code. The coding is started with the style tag. For example,

<style type="text/css">