Does the website work without a connection?
Yes. A page you have opened before shows its last saved copy, marked as one, and a change you make waits in this browser and sends itself when you are back online.
From the guide Working offline.
On the website
The website holds your changes the same way, under the same rules. A change made with no connection waits in this browser and sends itself as soon as the connection is back while Seayora is open in a tab — or the next time you open Seayora in the same browser. A card in the bottom-left corner says how many are waiting; open it to see each one, send them now, or discard one. Payments, sign-ins and calls still have to happen while you are connected, exactly as on the phones.
Read the whole guide: Working offline