Why are my elements so large?

Just starting with jQuery UI tonight and have a page set up here with some very basic items set up (accordion): http://psg-admin.platinumsynergy.com/

I had a date picker as well but I'm having the same problem with all of my elements - why are they so massive? I was kind of hoping they'd be the size of the elements on the ThemeRoller: http://jqueryui.com/themeroller/#themeGallery