Old CSS displays when logged out

I recently updated the css for the theme of my site, the Graphene Theme. I made some basic changes on the style.css page such as increasing the size of the page and of the widget side bar to accomodate some slightly larger content.

Anyway, when I am logged in as an admin the site displays just fine. when I log out however, the site displays an old version of css that has an error in it I remember making when I was making the changes. Point being it’s a recent css, not the css that was there before I started updating.

Any ideas on how to fix this? All help is much appreciated.