header of rhtml template

Hi,
I wrote an rhtml view to generate the css stylesheet file for the web
page.
The url that I can generate is correct:
http://127.0.0.1:3000/stylesheets/99/style_software/r-firewall.css

But the r-firewall.css file properties are file type text/html because
in default all the view.rhtml generate text/html file.

Someone can tell me how I can change the file header and so the file
type in text/css of a view.rhtml?

Thank you.

Luigi