Cascading Style Sheets

Cascading Style Sheets (CSS) is a language used to define the presentation ("look and feel") of a document written in HTML or some other markup language.

Style sheet

See Style sheet (web design) for a discussion of style sheets.

Web page layout

CSS is fundamental to web page layout.

Separation of concerns

Separation of concerns is a design principle which requires certain entities to take certain responsibilities, and other entities to take other responsibilities.

In web design, separations of concerns includes the separation of:

• Style sheet provide design, presentation, layout, color
• Markup tags (HTML or XHTML) provides semantic content and structure

This design approach is identified as a "separation" because it largely supersedes the antecedent methodology in which a page's markup (HTML) defined both style and structure. (For example, the font element.)

Selectors

Selectors specify which HTML elements will be selected -- and thus affected -- by a style rule.

Fundamental selectors

• Class selector (CSS)
• HTML element selector (CSS)
• ID selector (CSS)

See also

• Cascade (CSS)
• Cascade weight (CSS)
• Class selector (CSS)
• Conditional stylesheets
• CSS hacks
• Declaration (CSS)
• External style sheet
• HTML element selector (CSS)
• ID selector (CSS)
• Less (stylesheet language)
• Responsive web design
• Sass (stylesheet language)
• Selector
• Separation of concerns
• Style sheet (web design)
• Web page layout

External links

• Cascading Style Sheets @ Wikipedia
• Introduction to CSS 2.1 @ W3C
• Mastering CSS Principles: A Comprehensive Guide @ Smashing Magazine
• 10 Principles of the CSS Masters @ tuts+
• CSS Architectures: Principles of Code Cleanup @ SitePoint
• CSS Best Practices for Team-Based Development @ Microsoft
• Don’t use IDs in CSS selectors?
• How To Develop Scalable And Maintainable CSS @ Vanseo Design
• DRY CSS - "A don't-repeat-yourself methodology for creating efficient, unified and Scalable stylesheets"
• Principles of writing consistent, idiomatic CSS
• Style Sheets Guide: The Cascade
• On HTML Element Identifiers
• Decoupling HTML From CSS