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

.game-board {
  width: 100%;
  height: 100vh;
  border-bottom: 30px solid green;
  margin: 0 auto;
  position: relative;
  overflow: hidden;
  background: linear-gradient(#87CEEB, #E0F6FF);
}

button {
  background: green;
  color: white;
  font-weight: bold;
  font-size: 1.5rem;
  border: none;
  padding: 1rem;
  position: absolute;
  right: 50vw;
  top: 50vh;
  cursor: pointer;
  z-index: 1;
}

button:hover {
  border: 2px solid green;
  background: none;
  color: green;
}

.game-over {
  width: 100%;
  height: 100vh;
  background: rgba(0, 0, 0, 0.322);
  display: none;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  position: fixed;
  top: 0;
  left: 0;
}

.game-over h1 {
  font-size: 3rem;
  color: red;
  text-align: center;
  margin-top: 15rem;
}

.pipe {
  position: absolute;
  bottom: 0;
  right: -80px;
  width: 80px;
}

.mario {
  width: 150px;
  position: absolute;
  bottom: 0;
}

.clouds {
  width: 550px;
  position: absolute;
  top: 0;
  animation: clouds-animation 20s infinite linear;
}

@keyframes clouds-animation {
  from {
    right: -550px;
  }

  to {
    right: 100%;
  }
}

.pipe-animation {
  animation: pipe-animation 2s infinite linear;
}

@keyframes pipe-animation {
  from {
    right: -80px;
  }

  to {
    right: 100%;
  }
}

.jump {
  animation: jump 800ms ease-out;
}

@keyframes jump {
  0% {
    bottom: 0;
  }

  40% {
    bottom: 200px;
  }

  50% {
    bottom: 200px;
  }

  60% {
    bottom: 200px;
  }

  100% {
    bottom: 0;
  }
}