The plugin allows customization of CSS files in a separate folder for the OrderStorm eCommerce plugin.
The User Manual provides complete instructions for managing your style sheets. Refer to the Table of Contents at http://www.orderstorm.com/wordpress-ecommerce/wordpress-shopping-cart-user-manual/ to find help. Note that this is not a tutorial on CSS. You must know the basics of how CSS works.
Send your questions and comments to email@example.com. Premium package users can call for phone support - see the Plans and Pricing page for information on which subscription levels come with phone support.