What is a WordPress Theme?

Definition of a Theme

A WordPress theme is a collection of template files that determine the overall design, layout, and main functions of a WordPress site. By simply changing the theme, the appearance and atmosphere of the site can change dramatically. For example, you can choose a design suited for blogs, corporate websites, or portfolios depending on your needs.

Difference Between Themes and Plugins

Themes handle the parts related to the “overall design and structure of the site,” while plugins are “tools to add specific functions.” For example, a contact form, SEO optimization, or site speed improvements can be achieved with plugins. Think of themes as appearance and plugins as functionality—it’s an easy way to remember.

Points to Consider When Choosing a Theme

Differences Between Free and Paid Themes

Free themes can be easily installed from the official WordPress directory and used without cost, which is their advantage. On the other hand, paid themes often feature higher design quality, unique functions, and strong support systems, making them suitable for business sites or serious operations.
Examples:

  • Free theme example: Twenty Twenty-Four
  • Paid theme examples: SANGO, THE THOR

Japanese Support Availability

It is also important to check if the theme supports Japanese and has a solid support system. Especially for beginners, having an official forum or support desk that responds in Japanese ensures peace of mind when problems arise. The availability of Japanese documentation and FAQs can also be a deciding factor.

Design and Customizability

Each theme has different design styles and ease of customization. Some themes allow customization without coding, while others may require knowledge of CSS or PHP. Check whether the theme has “a design that fits your site” and “an intuitive customization interface”.

How to Customize a Theme

Using the Customizer

WordPress includes a standard feature called the “Customizer.”
From the admin panel, go to “Appearance” → “Customize” to intuitively change site titles, colors, layouts, widget placements, and more.
Examples:
You can change the site title, background color, and add a header image while previewing the changes in real time.

Editing Widgets and Menus

“Widgets” are parts you can place in areas such as sidebars or footers. For example, you can drag and drop items like “Latest Posts,” “Search Box,” or “Banner Images.”
“Menus” let you set the link structure of the navigation bar, and can be easily edited from “Appearance” → “Menus” in the admin panel.

Editing with a Child Theme

By creating a dedicated theme (child) without modifying the original theme (parent), you can quickly respond to any issues without affecting the parent theme. The details will be explained in the next article.

Using and Creating a Child Theme (For Beginners)

If you want to customize a WordPress theme, using a “child theme” is highly recommended. A child theme inherits the functionality and design of the parent theme (the original theme) while allowing you to add your own customizations. Editing the parent theme directly risks losing your changes during updates, but using a child theme prevents overwriting from parent theme updates while letting you create your own customizations—a huge advantage.

Benefits of Using a Child Theme

  • Safe even if the parent theme is updated
    Your custom designs and functions will not be lost.
  • Easy troubleshooting by checking only the child theme
    When an issue occurs, it’s easier to locate the problem.
  • Easier customization management
    All changes are managed within the child theme.

How to Create a Child Theme (Basic Steps)

1. Create a Folder for the Child Theme

Inside the WordPress theme directory (e.g., wp-content/themes/), create a folder named like “parent-theme-name-child” (e.g., mytheme-child).

2. Create style.css

Create a style.css file with the following content and place it in the child theme folder.

/* 
Theme Name: ParentThemeName-child
Template: ParentThemeFolderName
*/

Example: If the parent theme is “twentytwentyfour”

/* 
Theme Name: twentytwentyfour-child
Template: twentytwentyfour
*/

3. Create functions.php

Create a functions.php file in the child theme folder. To load the parent theme’s styles, write the following:

<?php
// Child theme functions file
add_action( 'wp_enqueue_scripts', 'my_theme_enqueue_styles' );
function my_theme_enqueue_styles() {
  wp_enqueue_style( 'parent-style', get_template_directory_uri() . '/style.css' );
}

※ This code ensures the parent theme’s design is also applied.

4. Activate the Child Theme in WordPress Admin

From the admin panel, go to “Appearance” → “Themes” and activate the child theme you created.

A child theme may seem complicated, but all you need are two basic files (style.css and functions.php). You can copy and edit template files (e.g., header.php or footer.php) within the child theme to make more detailed customizations.

Things to Watch Out for When Changing Themes

Risk of Layout Collapse or Data Loss

When changing themes, widget placements, custom post types, or shortcode compatibility may not be maintained. This can cause layout collapse or partial data loss. Always check the site’s appearance before and after changing the theme.

Importance of Backups

Before changing the theme, always take a “full site backup.” Backups can be easily done with plugins (e.g., All-in-One WP Migration, UpdraftPlus) or server-side tools. This ensures you can restore the site immediately if problems occur.

Reconfiguring Plugins and Widgets

Depending on the theme, widget placements and plugin displays may be reset. After changing themes, always check “plugin functionality” and “rearrange widgets” as needed.

Summary
By understanding how to choose and customize WordPress themes properly, you can efficiently create your own unique website. If you face difficulties with theme selection or customization, consider using support services or community resources.