Proof 02 · obeys law 03
A chord that announces itself, and gives the keyboard back
A prefix key arms a second keystroke — Ctrl-B, then %. It is the strongest shortcut idiom there is, and the most commonly done badly, because the moment between the two keys is a mode the software has entered on your behalf. This one shows the mode, counts the time it has left out loud, releases the keyboard whether or not you press anything, and refuses to bind the chords the browser and the operating system already own.
1 pane
Nothing has run yet.
Only two keystrokes are ever intercepted: the prefix, while this panel has focus, and the one key that follows it. Space and the arrows still scroll the page, because this panel has no claim on them. Tab and Escape are never taken at all.
The keys above are also buttons. That is not a fallback — every terminal on a phone ships a soft key row, because a phone keyboard has no Ctrl and a terminal is unusable without one. Tapping runs the same chord: the same two-second window, the same refusals, the same announcements.
Law 03
A shortcut announces itself, and never steals.
Discoverable without documentation. Never overrides a browser or screen-reader binding. Chords time out and say so.