Basic Selectors

universal

the * represents any tag, id or class, use this sparingly for definitions: * { font-style: italic }

tag

tag selectors represent any single tag such as div or p: p { line-height: 150% }

id

id represents a unique identifier in the document: h3#headline { font-style: italic }

class

classes can be used on any number of elements, on any type of element: li.menuitem { font-weight: bold }

tree selectors

descendent( )

this applies to a selector that is anywhere in the tree beneath the parent

child(>)

this selects only a selector immediately below the parent

adjacent(+)

this selects any item on the same level as the sibling

attribute[attr]

this selects any item with the specified attribute

pseudo-tags

:focus

(only valid on form elements and links) applies style to element when user is focused here

:hover

applies to any element that the mouse is over

:active

applies to links that are actively being clicked

:visited

applies to followed links

:link

applies to links that have never been followed

non-interactive psuedo-classes

:first-child

The :first-child pseudo-class matches an element that is the first child of some other element.

:first-line

The :first-line pseudo-element applies special styles to the first formatted line of a paragraph.

:first-letter

The :first-letter pseudo-element may be used for "initial caps" and "drop caps"

:before, :after

The ':before' and ':after' pseudo-elements can be used to insert generated content before or after an element's content.

cascade

default

These are the default values as defined by the browser

user

These are the values the user can set on his/her client to override the browser defaults

author

These are set by the page author and override both user and default values

!important

user

If a user adds !important to his/her stylesheet, it will override the author's settings, regardless of whether the author set !important

others

In any other location, a rule with !important will override any other rule of the same attribute