body {
  margin: 0;
  font-family: sans-serif;
  background: #1f2430;
  color: #fff;
  text-align: center;
}
h1 { font-size: 22px; margin: 10px 0 4px; }
#hint { margin: 0 0 8px; color: #b8c0d0; font-size: 14px; }
#menu { display: flex; flex-wrap: wrap; gap: 6px; justify-content: center; padding: 0 8px 10px; }
#menu button {
  border: 0; border-radius: 6px; padding: 6px 10px; cursor: pointer;
  background: #3a4258; color: #fff; font-size: 14px;
}
#menu button.on { background: #ffd700; color: #222; }
canvas { max-width: 96vw; border: 4px solid #3a4258; border-radius: 8px; image-rendering: pixelated; }