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What Is CSS

Simple PUT......

Cascading Style Sheets (CSS) is a style sheet language used to describe the presentation semantics ( i.e. the look and formatting ) of a document written in a markup language. It's most common application is to style web pages written in HTML and XHTML, but the language can also be applied to any kind of XMLdocument, including plain XMLSVG and XUL.

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 layoutcolors, 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 can also allow the same markup page to be presented in different styles for different rendering methods, such as on-screen, in print, by voice (when read out by a speech-based browser or screen reader) and on Braille-based, tactile devices. While the author of a document typically links that document to a CSS style sheet, readers can use a different style sheet, perhaps one on their own computer, to override the one the author has specified.

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 typetext/css is registered for use with CSS.


Progressive Enhancement : The Methodology
Progressive Enhancement + Web Designer = Happy Users

It's all well and good to speak about the technical solutions CSS brings to the table, but we must mention Progressive Enhancement in the same breath. Progressive Enhancement simply put, means all content and functionality be based on well structured and semantic HTML that is usable on all web enabled devices, mobile phones, gaming systems while CSS and Javascript are layered on top unobtrusively. 

Task Discussion

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  • Patti   Feb. 16, 2014, 7:54 p.m.
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  • Emily Priddy   June 19, 2012, 11:10 a.m.

    I think Graceful Degradation is also important for the same reasons.