body {
  margin:0;
  overflow:hidden;
  font-family: Arial, sans-serif;
  background: #111;
}

/* UI */
#ui {
  position: absolute;
  top:10px;
  left:10px;
  color:white;
  font-size:24px;
  z-index:10;
}

/* Title Screen */
#titleScreen {
  position:absolute; top:0; left:0; width:100%; height:100%;
  display:flex; flex-direction: column; justify-content:center; align-items:center;
  background:#222; color:white; z-index:20;
}
#titleScreen h1 { font-size:60px; margin-bottom:20px; }
#titleScreen button {
  padding:15px 30px; font-size:24px; cursor:pointer;
  border:none; border-radius:8px; background:#00ff88; color:#111;
}

/* Game Over Screen */
#gameOverScreen {
  display:none;
  position:absolute; top:50%; left:50%;
  transform:translate(-50%, -50%);
  text-align:center; color:white; font-size:30px;
  background:rgba(0,0,0,0.8); padding:20px; border-radius:10px; z-index:20;
}
#gameOverScreen button {
  padding:10px 20px; font-size:20px; cursor:pointer;
  border:none; border-radius:5px; background:#00ff88; color:#111; margin-top:10px;
}