The train enters the tunnel; the document doesn't notice

You're rewriting chapter three on the 7:40 out of Lyon. LibreOffice runs in a container; your phone's browser renders it with ?reconnect=true. The train enters the tunnel. The screen freezes, then greys out. You put the phone down.

Nothing happened to the document. The desktop kept running on the server, holding every keystroke you'd typed. When the signal returns the client reconnects on its own and shows the current state, not the state you left. You pick up at the word you stopped on.

The same thing happens when the phone hops from café WiFi to cellular, or when a laptop lid closes. The connection is the only thing that travels. The session stays where the compute is, and the browser is just the window onto it.

Your network drops. Your work doesn't.