What exactly syncs across my devices, and what stays local?

Everything you would expect, all encrypted on your device before it syncs: notes, tasks, journal entries, your vault, and the encrypted files in it. Your settings follow you too - favorite tags, sort and view preferences, color theme, your PIN (as a salted hash, never the PIN itself), app lock, tracker and medication setup, and trash auto-delete. Set something up once and every device picks it up.

A few things stay deliberately device-local: light or dark mode (each device follows its own system preference), biometric unlock (tied to the hardware of each device), and your unlock state (closing the app always re-locks). The server only ever stores encrypted blobs and can read none of it.