body {
  background-color: black;
  background-size: cover;
}

#window {
  position: relative;
  max-width: 1000px;
  height: 1000px;
  margin: 2% auto auto auto;
  border: 5px solid red;
  overflow: hidden;
}

#sky {
  height: 700px;
  background-color: cyan;
}

#clouds {
  filter: brightness(100%);
  -webkit-filter: brightness(100%);
  animation-name: weather;
  animation-duration: 20s;
  animation-iteration-count: infinite;
}

@keyframes weather {
  0% {
    filter: brightness(100%);
  }
  20% {
    filter: brightness(25%);
  }
  40% {
    filter: brightness(100%);
  }
  60% {
    opacity: 100%;
  }
  80% {
    opacity: 0%;
  }
}

#ground {
  max-width: 1000px;
  height: 300px;
  margin-left: auto;
  margin-right: auto;
  background-color: green;
}

#plane2 {
  width: 150px;
  position: absolute;
  top: 200px;
  right: -25%;
  animation-name: flyby;
  animation-duration: 12s;
  animation-iteration-count: infinite;
  animation-timing-function: linear;
}

@keyframes flyby {
  from {
    right: -25%;
  }
  to {
    right: 110%;
  }
}

#copter1 {
  width: 200px;
  position: absolute;
  bottom: 250px;
  right: 20%;
  animation-name: takeoff;
  animation-duration: 20s;
  animation-iteration-count: infinite;
}

@keyframes takeoff {
  10% {
    bottom: 500px;
    transform: translateX(0px) rotateY(0);
  }
  20% {
    bottom: 500px;
    transform: translateX(0px) rotateY(0) rotateZ(-25deg);
  }
  25% {
    bottom: 500px;
    transform: translateX(-400px) rotateY(0);
  }
  30% {
    bottom: 500px;
    transform: translateX(-400px) rotateY(0);
  }
  40% {
    bottom: 500px;
    transform: translateX(-400px) rotateY(180deg);
  }
  50% {
    bottom: 250px;
    transform: translateX(-400px) rotateY(180deg);
  }
  60% {
    bottom: 500px;
    transform: translateX(-400px) rotateY(180deg);
  }
  70% {
    bottom: 500px;
    transform: translateX(-400px) rotateY(180deg) rotateZ(-25deg);
  }
  75% {
    bottom: 500px;
    transform: translateX(0px) rotateY(180deg);
  }
  80% {
    bottom: 500px;
    transform: translateX(0px) rotateY(180deg);
  }
  90% {
    bottom: 500px;
    transform: translateX(0px) rotateY(0);
  }
  100% {
    bottom: 250px;
    transform: translateX(0px) rotateY(0);
  }
}

#car1 {
  width: 150px;
  position: absolute;
  bottom: 50px;
  margin-left: 5%;
  animation-name: vroom;
  animation-duration: 8s;
  animation-iteration-count: infinite;
}

@keyframes vroom {
  0% {
    margin-left: 5%;
  }
  30% {
    margin-left: 80%;
  }
  60% {
    transform: rotateY(180deg);
  }
  100% {
    margin-left: 5%;
  }
}