:root { color-scheme: dark; font-family: Arial, Helvetica, sans-serif; }
* { box-sizing: border-box; }
html, body { width:100%; height:100%; margin:0; overflow:hidden; background:#11151b; }
body { display:grid; place-items:center; }
#app { width:100vw; height:100vh; display:grid; place-items:center; padding:8px; }
#game {
  display:block;
  width:min(calc(100vw - 16px), calc((100vh - 16px) * 4 / 3));
  height:min(calc(100vh - 16px), calc((100vw - 16px) * 3 / 4));
  aspect-ratio:4/3;
  background:#e9edf1;
  border:0;
  outline:none;
  box-shadow:0 8px 34px rgba(0,0,0,.42);
  touch-action:none;
  user-select:none;
}
#game:focus-visible { outline:2px solid #fff; outline-offset:2px; }