sonunigam (Love Geek): A pseudo-class selects entire elements, such as :link 0r :visited, whereas a pseudo-element makes a selection that may consist of partial elements, such as :first-line 0r :first-letter. *
04-01-11 - 00:31:16

sonunigam (Love Geek): Selectors may be combined in other ways too, especially in CSS 2.1, to achieve greater specificity and flexibility. *
04-01-11 - 00:32:33

sonunigam (Love Geek): Here is an example summing up the rules above:

selector [, selector2, ...][:pseudo-class] {
property: value;
[property2: value2;
...]
}
/* comment */ *
04-01-11 - 00:36:34

sonunigam (Love Geek):
Use
Prior to CSS, nearly all of the presentational attributes of HTML documents were contained within the HTML markup; all font colors, background styles, element alignments, borders and sizes had to be explicitly described, often repeatedly, within the HTML. CSS allows authors to move much of that information to a separate style sheet resulting in considerably simpler HTML markup. *
04-01-11 - 00:38:57

sonunigam (Love Geek): Headings (h1 elements), sub-headings (h2), sub-sub-headings (h3), etc., are defined structurally using HTML. In print and on the screen, choice of font, size, color and emphasis for these elements is presentational. *
04-01-11 - 00:39:41