You can build this by using face-api.js to handle face recognition right in the browser (so it works offline). Store data with localForage (easy offline database), and use PapaParse to let teachers download attendance as a CSV file. For the look and feel, just use Bootstrap to keep the design simple and mobile-friendly. Finally, make it a PWA so the app works even without internet and syncs later when online.

• face-api.js → face recognition.

• localForage → offline storage.

• PapaParse → CSV export.

• Bootstrap → UI design.

• PWA (service worker) → offline mode + installable.