Saksham-Mann/Daylign ? reverse-engineered prompt

Build me a calm daily planning app called Daylign that helps people keep track of habits, study routines, checklists, and sticky notes in one place.

I want a simple single page app where users can sign in with Firebase or use it as a guest, then create activity categories like Study, Health, or Deep Work. Inside each category they should be able to make checklists, add tasks, mark them done, rename them, reorder them, and see progress clearly. Some checklists should reset every day, while others stay permanent. A built in stopwatch for tasks would be great too, with timing that can start, pause, resume, and save when a task is finished.

Also include a sticky notes board with drag and drop ordering, pinning important notes to the top, and a modal for editing notes in different pastel colors. Add a dashboard that shows active timers, pinned notes, and quick actions. Make it feel clean, soft, and distraction free, and keep data synced online with offline caching so it still works when the connection is weak.