* {
  box-sizing: border-box;
  padding: 0;
  margin: 0;
}

body {
  background-color: #e9e9e9;
  font-family: 'Segoe UI', sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}

#gameContainer {
  position: relative;
}

canvas {
  border: 2px solid #333;
  background-color: #ffffff;
  display: block;
}

#ui {
  position: absolute;
  top: 10px;
  left: 10px;
  color: #222;
  font-size: 20px;
  font-weight: bold;
}

#restartButton {
  margin-top: 10px;
  padding: 8px 16px;
  font-size: 18px;
  display: block;
}

#startScreen,
#gameOverScreen {
  position: absolute;
  top: 40%;
  left: 50%;
  transform: translate(-50%, -50%);
  text-align: center;
  color: #333;
  background: rgba(255,255,255,0.9);
  padding: 20px;
  border-radius: 12px;
  box-shadow: 0 0 15px rgba(0,0,0,0.2);
}