Product. PSD to HTML / XHTML, CSS, Skin / Theme, Shopping Cart & CMS. 53 CSS-Techniques You Couldn’t Live Without. CSS is important.
And it is being used more and more often. Cascading Style Sheets offer many advantages you don’t have in table-layouts - and first of all a strict separation between layout, or design of the page, and the information, presented on the page. Thus the design of pages can be easily changed, just replacing a css-file with another one.