body {
  margin: 0;
  font-family: Arial, sans-serif;
  overflow: hidden;
  background-color: #333;
}

.hud {
  position: absolute;
  top: 10px;
  left: 10px;
  color: white;
  background: rgba(0, 0, 0, 0.5);
  padding: 10px;
  border-radius: 8px;
  font-family: 'Arial', sans-serif;
}

.hud h1 {
  margin: 0;
  font-size: 24px;
}

.hud p {
  margin: 5px 0 0;
  font-size: 14px;
}

a-scene {
  width: 100vw;
  height: 100vh;
  display: block;
}

a-sky {
  animation: skyAnimation 30s linear infinite;
}

a-plane {
  animation: planeAnimation 60s linear infinite;
}

@keyframes skyAnimation {
  0% { color: #87CEEB; }
  50% { color: #FFD700; }
  100% { color: #87CEEB; }
}

@keyframes planeAnimation {
  0% { color: #7BC8A4; }
  50% { color: #228B22; }
  100% { color: #7BC8A4; }
}