focusity-team/Focusity ? reverse-engineered prompt

Build me a simple web app called Focusity that helps someone stay focused during work sessions.

I want a clean, modern interface where a person can start a focus session, see a timer running, pause or stop it, and review their recent sessions later. Make it feel calm and distraction free, with a homepage, a main focus screen, and a small history area so users can see what they completed. If it makes sense, add a few basic stats like total time focused today and the number of sessions finished.

Use a straightforward full stack setup with a frontend and backend, and make sure the app works smoothly end to end. Keep the design polished and responsive so it looks good on desktop and mobile. If you need current best practices or docs for anything, look them up online first.