How to Implement a Dark Theme with a Toggle for Your Website

In this blog post, we will guide you through the step-by-step process of implementing a dark theme with a toggle for your website. By the end of this tutorial, you will have an interactive website that allows users to switch effortlessly between light and dark modes.

Step 1: Setting Up the HTML Structure

To get started, create an HTML file that will serve as the foundation for your dark-themed website. Include the necessary CSS and JavaScript files to handle the theme switching functionality. The basic HTML structure should look like this:

<!DOCTYPE html>
  <title>Your Website</title>
  <link rel="stylesheet" href="styles.css">
  <!-- Your website content goes here -->

  <button id="theme-toggle">Toggle Theme</button>

  <script src="script.js"></script>

Step 2: Defining CSS Styles for Both Themes

In the CSS file (styles.css), define the styles for both the light and dark themes. We recommend using CSS custom properties (variables) to make it easier to switch between themes. Here’s an example of how to set up the CSS styles:

/* Light theme */
:root {
  --background-color: #f5f5f5;
  --text-color: #333;

body {
  background-color: var(--background-color);
  color: var(--text-color);

/* Dark theme */
.dark-theme {
  --background-color: #333;
  --text-color: #f5f5f5;

Step 3: Adding JavaScript for Theme Toggle

To handle the theme switching functionality, create a JavaScript file (script.js). We’ll use JavaScript to toggle a class on the body element, which will apply the dark theme styles when the class is present. The JavaScript code should look like this:

// Get the theme toggle button element
const themeToggle = document.getElementById('theme-toggle');

// Function to toggle the dark theme
function toggleDarkTheme() {

// Event listener for the theme toggle button
themeToggle.addEventListener('click', toggleDarkTheme);

Step 4: Customizing the Theme Toggle Button

To make the theme toggle button more visually appealing, you can customize its appearance using CSS. Feel free to add your preferred styling, such as changing the button’s background color, font size, and border radius. Here’s an example of how to customize the button:

/* Example of customizing the theme toggle button */
#theme-toggle {
  background-color: #007bff;
  color: #fff;
  border: none;
  padding: 10px 20px;
  border-radius: 5px;
  cursor: pointer;

Step 5: Optional - Saving User Preference with Local Storage

To enhance user experience, you can store the user’s theme preference using the browser’s Local Storage. This way, the website can remember the user’s chosen theme when they return to the site. Here’s how you can implement this feature:

// Check if the user's theme preference is already set
const userThemePreference = localStorage.getItem('theme');

// If the preference is set, apply the theme
if (userThemePreference === 'dark') {

// Event listener for the theme toggle button
themeToggle.addEventListener('click', () => {
  // Toggle the dark theme class on the body element

  // Save the user's theme preference to Local Storage
  const currentTheme = document.body.classList.contains('dark-theme') ? 'dark' : 'light';
  localStorage.setItem('theme', currentTheme);


Implementing a dark theme with a toggle for your website is a great way to provide users with a more personalized and visually appealing experience. By following the step-by-step guide in this blog post, you can effortlessly add this feature to your website. Users will have the option to switch between light and dark themes with a simple click, and their preference will be remembered when they return. Embrace the dark side and enhance your website’s aesthetics and usability today!