:root {
  --main-background-color: #87CEEB;
  --game-container-background-color: #2ecc71;
  --player-background-color: #e74c3c;
  --obstacle-background-color: #f39c12;
}

body {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
  margin: 0;
  background-color: var(--main-background-color);
}

#game-container {
  position: relative;
  width: 400px;
  height: 200px;
  background-color: var(--game-container-background-color);
  overflow: hidden;
}

#player {
  position: absolute;
  bottom: 0;
  left: 50px;
  width: 50px;
  height: 50px;
  background-color: var(--player-background-color);
}

.obstacle {
  position: absolute;
  bottom: 0;
  width: 30px;
  height: 30px;
  background-color: var(--obstacle-background-color);
}