WordPress displays CSS instead of page contents

Hello,

On a new site I am currently working on, suddenly some of the pages are displaying as the contents of style.css instead of the page contents when you view the site.

I haven’t made any changes to the pages in question and only noticed it when I created a new page and tried to view it. The pages affected are About, Contact, Exhibitions and any new pages I try to create.

The site is http://www.bridgetlansley.com. The theme I am using is 2010.
Have these pages become corrupt in some way?

I would appreciate any advice that anyone might have. Thank you.