I enabled the Bartik theme and made it the default, but the home page of the site, or any other pages I add, do not have the theme applied to them. The most noticeable difference is that the regions do not have any background colours that the Bartik theme is meant to define.
I tried clearing the cache and using a different browser. i'm new to Drupal, but have tried reading the documentation and this just gives the impression that once you enable a theme and make it the default, it should apply to your pages.
Here's a screenshot of the top of the home page:
and here's what the Bartik theme is meant to look like: