Advanced Tutorials

Implementing a Light/Dark Theme Toggle with GeneratePress


In this tutorial, we’ll walk through the steps to add a light/dark theme toggle to your website using the GeneratePress theme. This feature enhances user experience by allowing visitors to switch between themes according to their preferences.


  • Basic knowledge of JavaScript and CSS.
  • A WordPress website with the GeneratePress theme installed.

Step 1: Understanding the Code

First, let’s break down the provided JavaScript and CSS code.

JavaScript Code Explanation

  • UUID.themes: This object holds the color schemes for dark and light themes.
  • UUID.applyTheme(): A function to apply the selected theme by changing CSS variables.
  • UUID.toggleLogo(): Changes the website logo depending on the theme.
  • Initial Theme Setup: Checks for saved themes or system preferences and applies them.
  • Theme Switch Event Listener: Toggles the theme when the switch is clicked.

CSS Code Explanation

  • .theme-switch-wrapper: Styles the theme switch container.
  • .theme-switch: Hides the checkbox and styles the slider.
  • Transition Effects: Adds smooth transitions when the theme is switched.

Step 2: Adding the Toggle HTML Code

  1. Open your WordPress dashboard.
  2. Navigate to Appearance > Theme Editor.
  3. Select the functions.php file.
  4. Paste the JavaScript code at the end of the file.
  5. Click Update File.
 * Add the toggle button the primary main menu for WordPress.
function uuid_add_theme_switch_toggle( $items, $args ) {
	if ( $args->theme_location === 'primary' ) {
		$items .= '<div id="theme-switch" class="theme-switch-wrapper">
			<label for="theme-switch-checkbox" class="theme-switch">
				<input type="checkbox" id="theme-switch-checkbox" name="theme-switch-checkbox" />
				<div class="slider round"></div>
	return $items;

add_filter( 'wp_nav_menu_items', 'uuid_add_theme_switch_toggle', 10, 2 );

Step 3: Integrating the CSS

  1. In the Theme Editor, select the style.css file.
  2. Add the provided CSS code for the theme switch.
  3. Update the file.

Step 4: Adding the Toggle Button

  • The provided PHP function uuid_add_theme_switch_toggle() adds the toggle button to the primary menu.
  • Add this function to your functions.php file.

Step 5: Testing

  • Visit your website and ensure the toggle appears in the primary menu.
  • Test the toggle to switch between light and dark themes.
  • If you already have a building site and have used only the Block editor to build your site you have used var(–color-name) in your custom stylesheet files then you won’t need to make many changes to make the dark/light theme look good.


Congratulations! You’ve successfully added a theme toggle to your GeneratePress website. This feature not only improves aesthetics but also enhances accessibility and user experience.


If you encounter issues:

  • Check for any syntax errors in the code.
  • Ensure that the JavaScript and CSS codes are correctly placed.
  • Clear your browser cache to see the changes.

By Krasen Slavov

WordPress theme and plugin developer, blogger, ultra-distance runner, and mountain lover.

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