On the Powered by Thottbot page, it says you can put your own divs in the tooltip using the tt tag, but it doesn't give an example of syntax.

I've made a div:
popup {
  width: 400px;
  height: 300px;
  background-color: black;
  color: white;
  border: 1px solid white;
  z-index: 300;
  }

and the code in my (Blogspot) post is this:
<b tt=#popup>text text text</b>

I want to put text in that div, but I don't know where to put it.

Please help!