Dark mode has become a popular feature across websites, apps, and operating systems. It reduces eye strain, conserves battery life on OLED screens, and enhances user experience. Many users prefer dark mode, so implementing it on your website can improve accessibility and engagement. This guide will walk you through the process of adding dark mode functionality to your website.

1. Why Implement Dark Mode?

Before jumping into the technical aspects, let’s look at why dark mode is beneficial:

• Improved User Experience – Dark mode is easier on the eyes, especially in low-light environments.
• Energy Efficiency – OLED and AMOLED screens consume less power in dark mode.
• Modern Aesthetic – Many users appreciate the sleek and stylish look of dark themes.
• Accessibility – Users with light sensitivity or certain visual impairments find dark mode more comfortable.

2. Using CSS to Create a Dark Mode Theme

The simplest way to add dark mode to your website is by using CSS custom properties (variables).

Step 1: Define Light and Dark Mode Styles

Create a default light theme and a dark theme using CSS variables.

:root {   --bg-color: #ffffff;   --text-color: #000000; } .dark-mode {   --bg-color: #121212;   --text-color: #ffffff; } body {   background-color: var(--bg-color);   color: var(--text-color);   transition: background-color 0.3s, color 0.3s; }

This code sets the default light mode colors and defines a .dark-mode class that applies the dark theme.

Step 2: Add a Dark Mode Toggle Button

You need a button that lets users switch between light and dark modes. Add this inside your HTML:

<button id="dark-mode-toggle">Toggle Dark Mode</button>

Now, add a JavaScript function to switch themes when the button is clicked.

const toggleButton = document.getElementById('dark-mode-toggle');
const body = document.body;

// Check for previously saved mode
if (localStorage.getItem('darkMode') === 'enabled') {
  body.classList.add('dark-mode');
}

toggleButton.addEventListener('click', () => {
  body.classList.toggle('dark-mode');
  
  // Save user preference
  if (body.classList.contains('dark-mode')) {
    localStorage.setItem('darkMode', 'enabled');
  } else {
    localStorage.setItem('darkMode', 'disabled');
  }
});

This script:

• Checks if the user has a saved preference in localStorage.
• Toggles the .dark-mode class when the button is clicked.
• Saves the user’s choice so it remains applied on future visits.

3. Detecting System Preferences with CSS

Modern browsers support the prefers-color-scheme media query, which detects if the user prefers dark mode.

@media (prefers-color-scheme: dark) {
  :root {
    --bg-color: #121212;
    --text-color: #ffffff;
  }
}

This method automatically applies dark mode based on the user’s system settings. However, for greater control, combining this with a manual toggle is recommended.

4. Enhancing Dark Mode for Better UX

To ensure a smooth dark mode experience, consider these improvements:

• Adjust images – Light-themed images might not look good in dark mode. Use SVG filters or provide alternate versions.
• Dark mode-friendly UI elements – Buttons, forms, and cards should contrast well.
• Save user preferences – Store settings in localStorage or cookies.

Final Thoughts

Adding dark mode to your website enhances user experience and accessibility. By combining CSS variables, JavaScript toggles, and system preference detection, you can create a seamless dark mode experience. Implementing this feature makes your website modern, user-friendly, and customizable for all visitors.