RE: CSS
Hi Elizabeth,
CSS is Cascading Style Sheets.
It allows you to specify the look and feel of your web pages, and separates your content from your design.
It makes it easier to update your whole site, as you can link all your pages to just one style sheet. Then when you update your style sheet, all the pages will adopt the change.
CSS used to be just about colours and fonts. But now you can specify widths and heights of areas, and all sorts of page elements.
If you'd like to learn even more about CSS than you learnt on your Dreamweaver course, I'd recommend looking at http://www.w3schools.com/css/
It can be initially tricky to grasp and get the hang of it. But once you've mastered the basics, it can save a lot of time, and be very rewarding.
Regards, Rich