UtilityPage
The whole-screen state template — 404, 403, 500, offline — for when the app itself cannot render; reach for EmptyState when only a region came back empty, and Banner or Alert when the app still works and this is only a message. It replaces the view and brings its own background and Logo, so what you supply is copy and one primary way out, not a layout.
Usage
Examples
Error403
A permission wall rather than a failure: the copy names whose role is short and who can change it, so the reader knows the next move is a person and not a retry.
Error500
Ours to fix, said plainly, with the house reassurance that protection keeps running while the console does not. It is also the only story with a second button — one primary way out, at most one secondary.
Offline
The connection dropped, not the service: 'Try again' is the way out, and the copy promises automatic reconnection so nobody sits watching the button.