:root { color-scheme: dark; background: #000; color: #fff; }
* { box-sizing: border-box; }
html, body { margin: 0; width: 100%; min-height: 100%; }
body { min-height: 100dvh; display: grid; place-items: center; overflow: auto; }
main { width: 100%; display: grid; place-items: center; padding: 12px; }
canvas { display: block; image-rendering: pixelated; image-rendering: crisp-edges; outline: none; touch-action: none; cursor: none; border: 1px solid #fff; }
canvas:focus-visible { outline: 1px solid #fff; outline-offset: 3px; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; border: 0; }
@media (max-width: 540px) { main { padding: 4px; } }