SharwanKunwar/FocusPlanner — reverse-engineered prompt

Build me a clean productivity web app called Focus Planner where users can manage their daily tasks in a simple dashboard.

I want users to be able to add tasks, delete them, choose a priority like High, Medium, or Low, pick a due date, and filter tasks by date. Each task should look like a nice card with a clear priority ribbon or label, and there should be a way to open a small notes popup for extra task details. Make the layout responsive so it works well on desktop and mobile.

Use a modern React frontend with a polished UI, Tailwind styling, Ant Design style controls where useful, and simple global state so tasks update smoothly without a backend. Include a nice error page with an animation if possible, and make sure the app works correctly when deployed to Vercel, including page refreshes. Keep it frontend only for now and use in memory task data.