ok so... i have my css and stuff all done up in dreamweaver. is it all a lost cause?

--> not really, you will reuse all of that
Think of it like this: ZC still uses html, css and such to create the layout, but since ZC has many dynamic content created on-the-fly, the html is broken down to smaller parts (header, footer, left column, right column, etc....) and then put in different files/places.