Yes. After your first visit, the app caches everything needed to run offline. You can use it in airplane mode, in a courthouse basement with no signal, or anywhere else.
Your jury data is always stored locally in your browser, so it's available whether you're online or not.
What works offline: All core functionality — adding jurors, taking notes, tracking strikes, the gut score system, race/sex estimation, saving to file, and loading from file.
What requires internet: Team Sharing (syncing with other users), creating new shared sessions, and processing payments. If you lose connection during an active Team Sharing session, your changes are saved locally and will sync when you reconnect.