The document provides an overview of key Magento design concepts and terminology, including:
- Websites, stores, and store views which define the hierarchy and relationships between stores in a Magento installation.
- Design packages which are collections of related themes. Themes contain files that determine a store's visual output and functionality.
- Default themes which must be included in each design package. Theme variations allow for minor modifications to the default theme.
- Magento's theme fallback model loads missing files by searching themes in other packages, with the base package as the final fallback point.
This introduction defines common Magento terminology and concepts to provide context for customizing themes and packages.