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

.scene {
  position: relative;
  height: 100vh;
  overflow: hidden;
  background: linear-gradient(#a6d8ff, #fff, #fff);
}

.sun {
  position: absolute;
  top: 100px;
  left: 55%;
  width: 100px;
  height: 100px;
  background: #ffffff;
  border-radius: 50%;
  transform: translateX(-50%);
  box-shadow: 0 0 50px #ffffff;
  cursor: pointer;
  transition: 0.2s;
}

.scene.night {
  background: #222833;
}

.scene.night .sun {
  left: 45%;
  box-shadow: 0 0 0 #fff;
}

.scene.night .sun::before {
  content: "";
  position: absolute;
  top: -20px;
  left: 20px;
  width: 100%;
  height: 100%;
  background: #222833;
  border-radius: 50%;
}

.bg {
  position: absolute;
  bottom: 0;
  width: 100%;
  height: 280px;
  background: url(bg.png);
  animation: animateBg 25s linear infinite;
  background-size: 1500px;
  background-repeat: repeat-x;
}

@keyframes animateBg {
  0% {
    background-position-x: 0px;
  }
  100% {
    background-position-x: -1500px;
  }
}

.car1 {
  position: absolute;
  left: -200px;
  bottom: 20px;
  max-width: 200px;
  z-index: 1;
  animation: car1 18s linear infinite;
}

.car2 {
  position: absolute;
  right: -200px;
  bottom: 50px;
  max-width: 200px;
  /* z-index: 9; */
  animation: car2 12s linear infinite;
}

@keyframes car1 {
  0% {
    transform: translateX(0px);
  }
  90%,
  100% {
    transform: translateX(calc(100vw + 200px));
  }
}

@keyframes car2 {
  0% {
    transform: translateX(0px) rotateY(180deg);
  }
  90%,
  100% {
    transform: translateX(calc(-100vw - 200px)) rotateY(180deg);
  }
}
