body {
  margin: 0;
  font-family: "Courier New", monospace;
  background: #111;
  color: #0f0;
  text-align: center;
}

.screen {
  display: none;
  height: 100vh;
  justify-content: center;
  align-items: center;
  flex-direction: column;
}

.screen.active {
  display: flex;
}

canvas {
  background: black;
  border: 4px solid #0f0;
  image-rendering: pixelated;
}

button {
  padding: 10px 20px;
  font-size: 18px;
  background: black;
  color: #0f0;
  border: 2px solid #0f0;
  cursor: pointer;
}

.rules {
  list-style: none;
  padding: 0;
}

#countdown {
  font-size: 40px;
  margin-top: 20px;
}

#hud {
  margin-bottom: 10px;
  font-size: 20px;
}