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

body, html {
  height: 100%;
  font-family: Arial, sans-serif;
  background: linear-gradient(to bottom, #87CEEB, #fff);
  display: flex;
  justify-content: center;
  align-items: center;
}

#gameContainer {
  position: relative;
  width: 100%;
  max-width: 400px;
  aspect-ratio: 9 / 16;
  background: #70c5ce;
  overflow: hidden;
  border: 4px solid #333;
  border-radius: 10px;
}

#gameCanvas {
  width: 100%;
  height: 100%;
  display: block;
  background-color: #70c5ce;
}

#score {
  position: absolute;
  top: 10px;
  left: 50%;
  transform: translateX(-50%);
  color: white;
  font-size: 2em;
  font-weight: bold;
  z-index: 2;
}

#startBtn {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  padding: 15px 30px;
  font-size: 1.2em;
  background: #fff;
  border: 2px solid #333;
  border-radius: 8px;
  cursor: pointer;
  z-index: 2;
}