HTML and CSS Reference
Using this order ensures that your :hover styles will work whether a link has been visited or
not, and that your :active styles will be used even when a user is hovering over a link.
For more on link specificity, check out Eric Meyer's write-up on the subject (which also
includes some great points about calculating specificity in general): www.meyerweb.com/eric/
In what is one of the shortest (but still confusing) descriptions in the CSS specification, the W3C
has this to say about pseudo-elements ( www.w3.org/TR/CSS21/selector.html#pseudo-elements ):
Pseudo-elements create abstractions about the document tree beyond those specified by
the document language.
Well, now, that sums it up nicely, don't you think?
Pseudo-elements can be powerful weapons in your CSS arsenal, and include the follow-
ing four gems:
Their use is similar to that of pseudo-classes; however, pseudo-elements may only be
attached to the last simple selector in a combined selector (the element is targeted by the
selector, referred to by the W3C as the “subject”).
Caution The :first-line and :first-letter pseudo-elements are supported by IE 6 ( :before and
:after are still not supported by anyversion of IE/Win including IE 7 as of this writing), but there are some
pitfalls. For an up-to-date list (including IE 7 issues), visit Ingo Chao's site at www.satzansatz.de/cssd/
As you might guess, the :first-line pseudo-element targets the first line of the element to
which it is attached, and that element must be defined or styled as block-level , inline-block ,
table-caption , or table-cell . There is also a restricted list of properties that may be used: