/* App-wide full-screen toggle -- phone only.
   Visibility (and the phone/API gating) is driven from js/fullscreen.js via an
   inline display, matching the crystal full button's pattern. This sheet only
   swaps the two faces: corner arrows out to enter, in to exit. The .ic sizing
   comes from `.top-actions .icon-btn .ic` in app.css. */
#fullscreen-btn .ic-fs-exit { display: none; }
#fullscreen-btn.on .ic-fs-enter { display: none; }
#fullscreen-btn.on .ic-fs-exit { display: block; }