Cascading Style Sheets
Traditionally HTML was formatted using attributes within the tags. If you wanted a paragraph to have red text you just added color=red to the paragraph markup. That was simple but limited so CSS was invented.
CSS allows you to change the look and layout of Web pages. You create the page with HTML and then style it with CSS. CSS is very powerful so can take some learning. It can change colour, size, alignment and even make some items invisible or hidden behind others (which will make sense eventually!).
On this site you will learn HTML first (so that you can put stuff into a Web page). Once you can do that you will meet CSS and that is much more fun.
