How do you open/use a file with .css file extension?

[HappyPuppy]

I downloaded a manual for Freesco and when I unzipped it I got this file "style.css". When I open it it opens in MS FrontPage as some sort of html. It's supposed to be a manual. How do I use it?

 

[Argo]

css file is style sheets. They those files contain formatting information used in html files.

 

[Superwormy]

Doesn't sound like you extracted all the files... CSS files define the formatting for text in HTML files.