这是一个基本的WordPress问题，请熟悉主题主题的概念。

基本主题：https://codex.wordpress.org/Theme_Development子主题：https://codex.wordpress.org/Child_Themes

Theme hierarchy

Parent theme style.css

/*
Theme Name: Twenty Fifteen
Theme URI: https://wordpress.org/themes/twentyfifteen/
Author: the WordPress team
Author URI: https://wordpress.org/
Description: Twenty Fifteen
Version: 1.3
License: GNU General Public License v2 or later
License URI: http://www.gnu.org/licenses/gpl-2.0.html
Text Domain: twentyfifteen

This theme, like WordPress, is licensed under the GPL.
Use it to make something cool, have fun, and share what you\'ve learned with others.
*/

Child theme style.css

/*
 Theme Name:   Twenty Fifteen Child
 Theme URI:    http://example.com/twenty-fifteen-child/
 Description:  Twenty Fifteen Child Theme
 Author:       John Doe
 Author URI:   http://example.com
 Template:     twentyfifteen
 Version:      1.0.0
 License:      GNU General Public License v2 or later
 License URI:  http://www.gnu.org/licenses/gpl-2.0.html
 Tags:         light, dark, two-columns, right-sidebar, responsive-layout, accessibility-ready
 Text Domain:  twenty-fifteen-child
*/

这是WordPress中子主题工作原理的一个基本示例。您可以在模板文档中找到更多信息。