someshwar-songara/academic-diary ? reverse-engineered prompt

Build me a simple but polished academic diary web app for students, teachers, and an admin.

I want users to be able to sign up, log in, and get the right dashboard for their role. The admin should manage users and subjects. Teachers should be able to mark attendance, upload assignments and notes, and post announcements. Students should be able to see their attendance, upcoming deadlines, download materials, submit assignments, and keep a personal diary or study planner. A calendar view for events, holidays, and due dates would be great too.

Please make it responsive, clean, and easy to use, with a modern school portal feel. Use the existing PHP and MySQL setup, and wire it up so the main pages actually work end to end. Include a basic database setup, sample login accounts, and make sure file uploads and role based access are handled properly. If you need current docs for anything, look them up online.