Keyframes.app is a comprehensive toolbox for developers, offering a range of tools and features to enhance CSS and animations. With its browser-based and mobile-friendly design, users can create CSS @keyframe animations using a visual timeline similar to video editors. The site also provides options for creating single or multi-layer box shadows, as well as offering conversions, palettes, gradients, contrast ratios, and colorblindness features for colors. Users can search special characters and copy HTML and CSS codes. Keyframes.app also allows for customization with themes, data management, and other preferences. The site is local, ensuring that all user data stays on their device, and there is no third-party tracking, cookies, ad networks, or other plugins. It is also mobile-friendly and does not feature any social aspects or engaging content. Keyframes.app is free to use and open source, with the option for users to support and contribute to its development. For any feedback, suggestions, or issues, users can reach out via email, Twitter, or through the GitHub repository.