Cascading Style Sheets
Overview
 
Cascading Style Sheets (CSS) is a style sheet language used to describe the presentation semantics
Presentation semantics
In computer science, particularly in human-computer interaction, presentation semantics specify how a particular piece of a formal language is represented in a distinguished manner accessible to human senses, usually human vision. For example, saying that .....

 (the look and formatting) of a document written in a markup language
Markup language
A markup language is a modern system for annotating a text in a way that is syntactically distinguishable from that text. The idea and terminology evolved from the "marking up" of manuscripts, i.e. the revision instructions by editors, traditionally written with a blue pencil on authors' manuscripts...

. Its most common application is to style web page
Web page
A web page or webpage is a document or information resource that is suitable for the World Wide Web and can be accessed through a web browser and displayed on a monitor or mobile device. This information is usually in HTML or XHTML format, and may provide navigation to other web pages via hypertext...

s written in HTML
HTML
HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....

 and XHTML
XHTML
XHTML is a family of XML markup languages that mirror or extend versions of the widely-used Hypertext Markup Language , the language in which web pages are written....

, but the language can also be applied to any kind of XML
XML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....

 document, including plain XML
Plain Old XML
Plain Old XML is a term used to describe basic XML, sometimes mixed in with other, blendable specifications like XML Namespaces, Dublin Core, XInclude and XLink. People typically use the term as a contrast with complicated, multilayered XML specifications like those for web services or RDF...

, SVG
Scalable Vector Graphics
Scalable Vector Graphics is a family of specifications of an XML-based file format for describing two-dimensional vector graphics, both static and dynamic . The SVG specification is an open standard that has been under development by the World Wide Web Consortium since 1999.SVG images and their...

 and XUL
XUL
In computer programming, XUL , the XML User Interface Language, is an XML user interface markup language developed by the Mozilla project. XUL operates in Mozilla cross-platform applications such as Firefox...

.

CSS is designed primarily to enable the separation of document content (written in HTML or a similar markup language) from document presentation, including elements such as the layout
Page layout
Page layout is the part of graphic design that deals in the arrangement and style treatment of elements on a page.- History and development :...

, color
Color
Color or colour is the visual perceptual property corresponding in humans to the categories called red, green, blue and others. Color derives from the spectrum of light interacting in the eye with the spectral sensitivities of the light receptors...

s, and fonts
Typeface
In typography, a typeface is the artistic representation or interpretation of characters; it is the way the type looks. Each type is designed and there are thousands of different typefaces in existence, with new ones being developed constantly....

.
 
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