Overlapping horizontal tabs not working when CSS moved to external file

[Glen_S]

1) Script Title: Overlapping horizontal tabs

2) Script URL (on DD): http://www.dynamicdrive.com/style/cs...rizontal-tabs/

3) Describe problem: Maybe I am missing something, but when I take the CSS in this example and put it in its own file, then reference it from the web page, the tabs no longer show up.

[Glen_S]

haven't managed to solve this yet, any ideas?