The First-node Pseudo-class selects the first occurence of an element
in the document tree. If you omit an element selector, it SHOULD
select ALL first-occurrences of each element in the document tree.
Example
Ext/Doc: div:first-node
{ background-color: yellow }
(selects the first occurrence of a DIV element in the document and makes
its background yellow.)
In-Line: NA
Browser Peculiarities
Netscape 6.x: I'm not exactly sure how it is determining "first occurrence"
in some situations...some situations which I consider to be NOT "first
occurrence" are being selected - I wonder what order the document tree
is being examined in.