This is another question that I am sure is very simple. I've been working through tutorials on setting up a Drupal site from scratch with the Zen Theme. I have my Sub-Theme working just fine, thanks to https://drupal.org/node/1549668 and http://drupalonlinetraining.com/youtube/linwclark/drupal-7-basic-theming-zen-and-css
Now, I want to edit the CSS. Unfortunately, the documentation that I can find references 25 separate stylesheets (including both of these tutorials and this page.) The version I have, however, has far fewer sheets than that (13 according to the ReadMe).
I did find the ReadMe that describes the new stylesheets, but as this is my first foray into CSS within Drupal, I'm still a little unsure as to where I should start to add styles. Is it in normalize.css? Is this where I would add, for instance, a background image?
Thanks for any help, and/or for pointing me to a tutorial that breaks it down for the latest version of the Zen Theme!