Creating a child theme
|A child theme is the recommended way to modify an existing theme - it will keep your changes after updating the parent theme.
Child Themes « WordPress Codex
What is a Wordpress Child Theme
|Go to the wp-content\themes folder and create a yourparenttheme-child (this name format is recommended but not necessary) folder.|
|Create a style.css file in it|
|Enter the text from the picture in the file.
(1) Theme name: - required
(2) Template - required
/this field must have exactly the same name as the parent theme folder/
(3) @import url... - highly recommended
/this css file will override the parent's one and in most cases you'll want to keep its styles/
|The text from the picture above as text (for easy copy and pasting)
Theme Name: Twenty Eleven Child
Theme URI: http://example.com/
Description: Child theme for the Twenty Eleven theme
Author: Your name here
Author URI: http://example.com/about/
|Go to Appearance - Themes and you'll see the newly created child theme|
|You can copy and paste template files in your child theme for editing. These files (404.php, header.php) will override the parent's ones.
Note! - functions.php must be created empty because it is loading as addition to the parent's one (before it) .
|A sample functions.php file|