Welcome to the Core Concepts documentation. The goal of this chapter is to introduce you to the foundational concepts necessary for creating your own WordPress block themes.

The focus of this chapter is to help you familiarize yourself with the basic theme structure and standard files like style.css, functions.php, and theme.json. Once you have these core concepts down, you can more comfortably dive into the later chapters in this handbook.

Navigating this chapter

Use the following links to locate a topic within this chapter. Each article is listed in the recommended reading order for those new to theme development. For those with existing experience creating themes, feel free to jump to the section you need:

• Theme Structure: Walks through how a theme’s files and folders are structured following WordPress standards.
• Main Stylesheet: Explains the importance of the theme’s style.css file and how to use it.
• Custom Functionality: Dives into the theme’s functions file (functions.php) and how you can use it to add your own functionality to a theme.
• Templates: Introduces how WordPress’ block templates system works and provides pathways for deeper learning.
• Including Assets: A guide on including CSS, JavaScript, images, and more in your themes.
• Global Settings and Styles: Gives a basic overview of how the theme.json file works in themes with learning pathways to more detailed articles.