Hi there, you need to have the # in front of the top. So #top {background:#ffffff;} will make it white.

For making css changes, I use firebug in firefox. But you can also do the same with web developer tools in chrome etc. Here’s a short video showing how you can use the inspector to target elements and change on screen, then copy/paste the code back into the style.css and save – http://screencast.com/t/uCzOW06nUb4

To make things transparent, put background:none; instead of the hex value.