Add New stylesheet to Seasons theme

I've tried to add a custom stylesheet to the Seasons theme, but have not been able to get it to work. Basically I copied one of the stylesheets, renamed all of the appropriate classes, and added the new stylesheet to the config.ini. The new stylesheet appeared in the theme configuration on the Omeka dashboard, and when I selected it, it accurately copied the stylesheet I used, but when I started making changes to it, nothing happened.

Am I missing a step? Is this more trouble than it's worth? Should I just write over one of the existing stylesheets?