Mozilla's release of Firefox 67 introduces significant updates, including the innovative prefers-color-scheme media query, which enhances accessibility by allowing designs to adjust based on user preferences for light or dark themes. This feature, now supported by Firefox alongside Safari and soon Chrome, facilitates better web experiences for users with sensitivities or thematic preferences. Additionally, Firefox 67 improves user experience with the ability to run multiple profiles simultaneously and introduces the WebRender engine for better performance, alongside enhanced privacy controls that block cryptominers and fingerprinters. For developers, the update includes JavaScript's matchAll() method, the CSS revert keyword for default styling, and emphasizes using CSS variables for theming adjustments. While older browsers may lack support for these features, the update suggests employing progressive enhancement to accommodate various user environments.