Declarations

Structure and Rules

Table of contents:

Rules
Declarations
Pseudo-classes and Pseudo-elements
Cascading Order

Properties

A property is assigned to a selector in order to manipulate its style. Examples of properties include color, margin, and font.

Values

The declaration value is an assignment that a property receives. For example, the property color could receive the value red.

Grouping

In order to decrease repetitious statements within style sheets, grouping of selectors and declarations is allowed. For example, all of the headings in a document could be given identical declarations through a grouping:

H1, H2, H3, H4, H5, H6 {color: red; font-family: sans-serif }

Inheritance

Virtually all selectors which are nested within selectors will inherit the property values assigned to the outer selector unless otherwise modified. For example, a color defined for the BODY will also be applied to text in a paragraph.

There are some cases where the inner selector does not inherit the surrounding selector's values, but these should stand out logically. For example, the margin-top property is not inherited; intuitively, a paragraph would not have the same top margin as the document body.

Comments

Comments are denoted within style sheets with the same conventions that are used in C programming. A sample CSS1 comment would be in the format:

/* COMMENTS CANNOT BE NESTED */