body, html {
  margin: 0;
  padding: 0;
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: #87CEEB;
}

#home {
  position: fixed;
  top: 0;
  left: 0;
  margin: 10px;
  font-size: 18px;
  color: #fff;
  text-decoration: none;
  background-color: rgba(0, 0, 0, 0.5);
  padding: 5px 10px;
  border-radius: 5px;
  z-index: 1000;
}

#startScreen, #gameOverScreen {
  text-align: center;
}

#gameArea {
  width: 600px;
  height: 200px;
  background-color: #228B22;
  position: relative;
  overflow: hidden;
  border: 2px solid #000;
}

#player {
  width: 30px;
  height: 30px;
  background-color: yellow;
  position: absolute;
  bottom: 0;
  left: 50px;
  border-radius: 50%;
}

#obstacle {
  width: 20px;
  height: 30px;
  background-color: red;
  position: absolute;
  bottom: 0;
  right: 0;
  animation: moveObstacle 2s linear infinite;
}

@keyframes moveObstacle {
  0% { right: -20px; }
  100% { right: 100%; }
}

#scoreDisplay {
  position: absolute;
  top: 10px;
  left: 10px;
  font-size: 18px;
  color: white;
}

button {
  padding: 10px 20px;
  font-size: 16px;
  cursor: pointer;
}