CSS : Web Development Backbone

Cascading Style Sheets (CSS)

Cascading Style Sheets (CSS) is a style sheet language used for describing the presentation of a document written in a markup language like HTML. CSS is a cornerstone technology of the World Wide Web, alongside HTML and JavaScript.

CSS is designed to enable the separation of presentation and content, including layout, colors, and fonts. This separation can improve content accessibility, provide more flexibility and control in the specification of presentation characteristics, enable multiple web pages to share formatting by specifying the relevant CSS in a separate .css file, and reduce complexity and repetition in the structural content

Separation of formatting and content also makes it feasible to present the same markup page in different styles for different rendering methods, such as on-screen, in print, by voice (via speech-based browser or screen reader), and on Braille-based tactile devices. CSS also has rules for alternate formatting if the content is accessed on a mobile device.

The name cascading comes from the specified priority scheme to determine which style rule applies if more than one rule matches a particular element. This cascading priority scheme is 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). The W3C operates a free CSS validation service for CSS documents.

Syntax

CSS has a simple syntax and uses a number of English keywords to specify the names of various style properties.

A style sheet consists of a list of rules. Each rule or rule-set consists of one or more selectors, and a declaration block

Variations

CSS has various levels and profiles. Each level of CSS builds upon the last, typically adding new features and typically denoted as CSS 1, CSS 2, CSS 3, and CSS 4.

Advantages

1. Separation of content from presentation
2. Site-wide consistency
3. Bandwidth
4. Page reformatting
5. Accessibility

Disadvantages

1. Selectors are unable to ascend.
2. Cannot explicitly declare new scope independently of position
3. Pseudo-class dynamic behavior not controllable
4. Cannot name rules
5. Cannot include styles from a rule into another rule
6. Cannot target specific text without altering markup.

Alternative to CSS

At least for HTML and such. Adobe Postscript is the most likely alternative to CSS

PostScript (PS) is a page description language in the electronic publishing and desktop publishing business. It is a dynamically typed, concatenative programming language and was created at Adobe Systems.

PostScript is a Turing-complete programming language, belonging to the concatenative group. Typically, PostScript programs are not produced by humans, but by other programs. However, it is possible to write computer programs in PostScript just like any other programming language.

“HELLO WORLD”

A Hello World program, the customary way to show a small example of a complete program in a given language, might look like this in PostScript (level 2):

 %!PS
 /Courier             % name the desired font
 20 selectfont        % choose the size in points and establish 
                      % the font as the current one
 72 500 moveto        % position the current point at 
                      % coordinates 72, 500 (the origin is at the 
                      % lower-left corner of the page)
 (Hello world!) show  % stroke the text in parentheses
 showpage             % print all on the page