the folder sitesculptor_assets/content/ contains CSS and Image files used by the templates/sitesculptor_template.dwt file that is applied to the pages of your site.
the folder sitesculptor_assets/home/ contains CSS and image files used by the Index or Home page of your site.
both the index and content pages include a reference to the sitesculptor_css/mystyles.css file.
this file is intended for yo to use for adding any custom styles you wish to add, or to redefine and override the site sculptor classes.