The page you were opening cannot be fetched from anywhere — it is not in the device's memory yet. But whatever you have already used stays available: the calculators do their arithmetic offline, because all the formulas live inside the site itself.
The damage calculator, artillery, the cargo planner and run profitability — if you have opened them before.
Live player counts, news, the contract board and the chat: those are fresh data, and we are not going to invent them in place of the real thing.
A profile keeps your contracts and listings with you: sign in from your phone or your PC and everything is still there. You can post without one, but then the records live only in this browser.