A child theme in WordPress inherits the functionality of another "parent" theme and allows customizing or adding to its features. Using a child theme allows updating the parent theme without losing customizations and saves development time. To create a child theme, make a new folder in /wp-content/themes/ with at least a style.css file to override styles from the parent theme. This allows customizing the parent theme's design while receiving future updates.

2. What the heck is a child theme?
“A WordPress child theme is a theme that inherits
the functionality of another theme, called the parent
theme, and allows you to modify, or add to, the
functionality of that parent theme.”
- The WordPress Codex

3. What can I use a child theme for?
• Customize the parent site design
• Add in additional functionality
• Save a bunch of time

4. Why would I use a child theme?
• Update the parent theme without losing your
customizations
• Did I mention the part about saving time?

5. What do I need to get started?
• Choose a parent theme
(check out twentyten & twentyeleven)
• A new folder in /wp-content/themes/
• A CSS file in your new theme

6. The unedited parent theme

7. Create a new theme folder

8. Add a ‘style.css’ file

9. Overriding style elements
Parent Theme Child Theme

10. Activate your child theme
*screenshot.png

11. Customized twentyeleven theme

12. Twentyeleven header manager

13. Overriding existing functions

14. Overriding existing functions

15. Overriding existing functions

16. Adding your own functions

17. Adding your own functions

18. Keep in mind…
• Your child theme can contain as many or as few files
as you want
• Files in your child theme folder override files in the
parent theme folder
• Adding a functions.php will add-to rather than
override functions.php from your parent theme

19. Parent Theme vs Child Theme
Parent Theme Child Theme

20. Overriding files

21. Overriding files

22. Overriding files

23. Theme Frameworks
“A Theme framework is a Theme designed to be a
flexible foundation for quicker WordPress
development, usually serving as a robust Parent Theme
for Child Themes.”
- The WordPress Codex
• Genesis – studiopress.com
• Thematic – themeshaper.com
• Hybrid – themehybrid.com

24. Resources
• http://codex.wordpress.org/Theme_Development
• http://codex.wordpress.org/Child_Themes
• http://codex.wordpress.org/Plugin_API