Introduction to Bootstrap 5.3 Bootstrap 5.3 brings exciting new features and improvements to the world’s most popular CSS framework. Let’s explore what makes this version special. Dark Mode Support One of the most requested features is now built-in! Bootstrap 5.3 includes native dark mode support: <html data-bs-theme="dark"> <!-- Your dark mode content --> </html> You can easily toggle between light and dark themes: // Toggle dark mode document.documentElement.setAttribute('data-bs-theme', 'dark'); // Toggle light mode document.