Dark mode on a website – how to implement it and is it worth it?

Just a few years ago, dark mode was a novelty available mainly in mobile apps and operating systems. Today, dark mode has become a standard – used by both smartphone users and web browsers. More and more people value dark backgrounds not only for aesthetic reasons but also for practical ones – they reduce eye strain, make reading at night easier, and can help save energy on devices with OLED screens.

It’s no surprise, then, that website owners increasingly wonder whether implementing dark mode is a good move. In this article, we’ll take a closer look at what dark mode really is, the benefits and challenges it brings, and how to technically implement it on a website.

Dark Mode – what is it?

Dark Mode – definition

It’s a way of displaying content where a dark background (black, graphite, or navy) is combined with light text and graphic elements. In contrast to the classic light mode, where white dominates, dark mode reduces the overall screen brightness and introduces a more contrasting layout. Initially, it was mainly used in mobile apps and developer tools, but today it is increasingly available on websites as well.

Dark Mode vs Light Mode

The main difference between dark mode and light mode lies in the color scheme inversion:

• Light mode – light background, dark text; associated with clarity and the traditional look of websites.
• Dark mode – dark background, light text; perceived as modern and more comfortable in dark environments.

Users increasingly expect the option to choose, which is why toggles allowing them to switch modes with one click or adapt to the operating system settings have become popular.

Popularity of Dark Mode in apps and websites

Dark mode today is not just a trend but a common standard. All major operating systems – Android, iOS, Windows, and macOS – now offer built-in dark mode. Global platforms such as YouTube, Facebook, Instagram, Twitter (X), and Netflix have also implemented it permanently. As a result, users accustomed to dark interfaces in mobile and desktop applications expect the same convenience on websites.

Benefits of implementing Dark Mode

1. User comfort
   A dark background with light text puts less strain on the eyes, especially during extended use of a website or app in the evening or at night.
2. Modern look
   Dark mode is associated with innovation and minimalism. Websites offering dark mode are often perceived as more aesthetic and aligned with current design trends.
3. Energy saving
   On devices with OLED and AMOLED screens, dark mode can actually reduce energy consumption, resulting in longer battery life.
4. Adapting to user preferences
   More and more people are used to dark mode in apps and operating systems. Allowing users to choose on a website improves UX and increases satisfaction.
5. Brand differentiation
   Companies that implement modern solutions build the image of being innovative and user-focused. Dark mode can be part of brand strategy and a competitive advantage.

Disadvantages of Dark Mode

1. Readability issues
   Not all text on a dark background is easy to read – especially if there is insufficient contrast between colors. A poorly chosen color palette can make content harder to consume.
2. Lack of universality
   While many users prefer dark interfaces, there is still a group for whom light mode is more comfortable. Offering only dark mode may limit accessibility.
3. Additional implementation and testing costs
   Designing and maintaining two color versions of a website requires extra work – both from designers and developers. There are also testing costs to ensure dark mode works correctly across different devices and browsers.
4. Consistency of visual identity
   Not every brand looks good in dark colors. Some logos or graphic elements may lose readability and require adjustments.

How to implement Dark Mode in WordPress?

1. Preparing the environment

• Log in to your WordPress (administrator account).
• Make sure you have access to theme files (e.g., via FTP, cPanel, or your hosting file manager).
• Work preferably on a child theme so updates don’t overwrite your changes.

Don’t know what a child theme is or how to create one? Check our article:

WordPress Child theme – what is it, why use it, and how to create one?

WordPress Child theme – customize your website while keeping it secure and updatable without losing modifications. Learn how to enhance your site!

read more

2. Creating asset files

In your theme directory (preferably in the child theme), create this structure:

/assets/css/base.css
/assets/css/theme.css
/assets/js/theme.js

• base.css → base styles for your site (layout, components), but all colors should use CSS tokens (var(--bg), var(--fg), etc.).
• theme.css → definitions of color variables for light and dark modes.

:root {
--bg: #ffffff;
--fg: #111111;
--primary: #2563eb;
}
:root[data-theme="dark"] {
--bg: #0b0d11;
--fg: #e8eaed;
--primary: #60a5fa;
}
body {
background: var(--bg);
color: var(--fg);
}
a { color: var(--primary); }

• theme.js → theme-switching logic (single file, no inline code). This file:
  • checks user system settings,
  • sets data-theme="light" or "dark" on the <html> tag,
  • remembers the user’s choice in localStorage,
  • handles toggle button clicks.

3. Adding a toggle button

In your site header template (header.php or menu file), insert a button:

<button id="theme-toggle" aria-pressed="false" aria-label="Change theme">🌙/☀️</button>

4. Enqueueing assets in WordPress

Open your theme’s functions.php (child theme) and add:

add_action( 'wp_enqueue_scripts', function () {
$theme_uri = get_stylesheet_directory_uri();
$theme_dir = get_stylesheet_directory();

// versioning by file modification time (cache-busting)
$base_css = '/assets/css/base.css';
$theme_css = '/assets/css/theme.css';
$theme_js = '/assets/js/theme.js';

wp_enqueue_style( 'site-base', $theme_uri . $base_css, [], filemtime($theme_dir . $base_css) );
wp_enqueue_style( 'site-theme', $theme_uri . $theme_css, ['site-base'], filemtime($theme_dir . $theme_css) );
wp_enqueue_script( 'site-theme-js', $theme_uri . $theme_js, [], filemtime($theme_dir . $theme_js), false );
});

Thanks to this:

• Your styles (base.css, theme.css) and script (theme.js) will be automatically included,
• JS will load in <head> (this prevents a “flash” of light background before switching to dark mode).

5. Testing functionality

• Refresh the page in your browser.
• Check if the theme adapts to system settings (light/dark).
• Click the toggle button – the theme should switch instantly.
• Navigate to another page – the theme should remain as chosen.

6. Accessibility tests

After implementation, check:

• text and interactive element contrast (min. WCAG),
• focus visibility (e.g., border when tabbing),
• forms (inputs, selects, error messages),
• logos/icons – whether they are legible on dark background,
• embedded content (YouTube, maps, widgets) – whether it adapts to dark mode.

Best practices for Dark Mode

Ensuring proper contrast

A dark background doesn’t mean pure black (#000). Dark shades of gray or navy work better, being less tiring for the eyes. Text should have a contrast ratio of at least WCAG AA (4.5:1), and for large headings – 3:1.

Consistency with brand identity

Brand colors should be adjusted for dark mode. Sometimes they need to be brightened or saturated to remain visible on a dark background while retaining brand character.

Readability of interactive elements

Buttons, links, forms, and icons must be clear in both modes. In dark mode, strong borders and emphasized hover/focus states help users recognize clickable elements.

User flexibility

The best solution is a mode toggle – let visitors choose whether they prefer light or dark mode. It’s also worth auto-detecting system preferences (prefers-color-scheme), but the decision should always be up to the user.

Optimizing for various content

1. Graphics, logos, and photos must be checked in both versions so they don’t “disappear” on dark background.
2. Consider alternative graphics (e.g., light logo for dark background).
3. Embedded content (maps, videos, plugins) should support dark mode or have a frame/background to improve visibility.

Avoiding flash of unstyled theme (FOUC)

When loading a page, a temporary “flash” of light background may appear. To avoid this, the theme should be set as early as possible (e.g., using the data-theme attribute set by a script before page rendering).

Testing and accessibility

Dark mode must be tested on different devices and under different conditions – during the day, at night, on OLED and LCD screens, and with accessibility modes. This ensures comfort for all users.

Summary

Dark mode is no longer a passing trend but a feature increasingly expected by website users. A well-designed dark mode enhances user comfort, boosts visual appeal, and can positively influence overall user experience. At the same time, it requires thoughtful implementation – from choosing colors and contrasts to accessibility testing and providing user flexibility.

The decision to introduce dark mode should depend on the website’s nature and target audience. In many cases, it will be a valuable UX element and competitive advantage, but it doesn’t always have to be a priority. The most important thing is that dark mode is not only aesthetic but also readable, accessible, and consistent with the brand’s identity.