body {
  background: #222;
  color: #eee;
  font-family: sans-serif;
  text-align: center;
  margin: 0;
  padding: 10px;
  user-select: none;
}

h1 {
  margin-bottom: 5px;
}

#ui {
  margin-bottom: 8px;
  font-size: 1.2rem;
  display: flex;
  justify-content: center;
  gap: 20px;
  align-items: center;
}

button {
  font-size: 1rem;
  padding: 6px 12px;
  cursor: pointer;
}

#message {
  margin-top: 12px;
  font-size: 1.5rem;
  color: #0f0;
  font-weight: bold;
}

.hidden {
  display: none;
}

canvas {
  border: 2px solid #eee;
  background: #87CEEB; /* sky blue */
  display: block;
  margin: 0 auto;
  image-rendering: pixelated;
  width: 640px;
  height: 480px;
}