23kulpamens on "Different CSS for each view."

Hi I would like to have different style file for each view in Wordpress. I had found a partially solution here: http://wordpress.org/support/topic/changing-location-of-stylecss-with-filters?replies=8

But how to detect from functions.php if I'm calling single.php or category.php . I think that there sould be something with add_action, but I can't figure it out.