Darkmode.js is a lightweight VanillaJS library created by Sandoche that uses CSS mix-blend-mode to add a dark mode or night mode toggle to any website in seconds.

The main features and capabilities of Darkmode.js include:

• Automatic Widget & Programmatic Control: Displays an automatic, floating toggle widget on the webpage or allows toggling dark mode programmatically using the toggle() method and checking activation state via isActivated().

• LocalStorage & OS Preference Detection: Automatically remembers user choice using localStorage by default and detects system-level dark themes via prefers-color-scheme media queries.

• CSS Inversion & Style Overrides: Uses mix-blend-mode: difference for color inversion without requiring a dedicated dark-mode stylesheet. It applies a .darkmode--activated class to the body element for custom CSS overrides and supports .darkmode-ignore or isolation: isolate to exclude specific elements.

• Configurable Appearance & Behavior: Provides customizable options for button placement (bottom, left, right), transition duration, blend and button colors, custom button labels, and cookie saving.

• CMS & Framework Integration: Installs easily via JSDelivr CDN snippets or npm, with dedicated plugins and modules available for WordPress, Drupal, and Nuxt.js.