At-Rules
= Index DOT Css by Brian Wilson [bloo@blooberry.com] =

At-Rules

@charset [CSS2]

Specifies the character encoding used in the external style sheet.

@import [CSS1 | CSS2 | IE4 | O3.5]

Imports a style sheet fragment file to the current style sheet.

@media [CSS2 | IE4 | O3.5]

Specifies style rules to be rendered only with specified media.

@page [CSS2]

Defines a page box.

@fontdef [N4]

Netscape's method for specifying an external font definition file.

@font-face [CSS2 | IE4]

Describes the characteristics of a particular font.

What Are At-Rules?

At-Rules extend CSS Rule Set syntax beyond simple Selector/Declaration blocks. Any functionality in CSS that does not fall under the umbrella of selector/style declaration pair bindings uses a special At-Rule syntax.

Syntax: An At-Rule begins with the "@" character followed immediately by a keyword. Following the keyword separated by a space is an At-rule statement appropriate to the At-keyword used. If the At-Rule is a simple declarative statement (charset, import, fontdef), it is terminated by a semi-colon (";".) If the At-Rule is a conditional or informative statement (media, page, font-face), it is followed by optional arguments and then a style declaration block inside matching curly braces ("{", "}".) At-Rules are sometimes nestable, depending on the context. If any part of an At-Rule is not understood, it should be ignored.

Syntax/Examples

Simple, declarative At-Rule

Syntax: @[Keyword] [arguments];

Example:

@import url(foo.css) screen;

Conditional/Informative At-Rule

Syntax: @[Keyword] [arguments] { [style declaration block] }

Example:

@media screen { color: green; background-color: yellow }