/* Fusion — square board, same screen recipe as Snake */
#fusionStage { max-width: min(640px, calc(100vh - 150px)); min-width: min(100%, 300px); margin: 0 auto; }
#fusionCanvas { aspect-ratio: 1; background: #0c0a14; }
#fusionStage:fullscreen { display: grid; place-items: center; width: 100vw; height: 100vh; background: var(--au-bg); padding: 18px; }
#fusionStage:fullscreen .game-canvas-wrap { width: min(92vh, 92vw); }

/* v3.7.3: width/height ratio used by the landscape layout in game-shell.css */
#fusionStage { --game-aspect: 1; }