.a_background {
  height: 100%;
  width: 100%;
}

.a_background_top {
  height: 71.6%;
  width: 100%;
  background-image: url("../images/background/a_background_top.png");
  background-size: 100% 100%;
}

.a_background_middle {
  height: 13.1%;
  width: 100%;
  background-image: url("../images/background/a_background_middle.png");
  background-size: 100% 100%;
}

.a_background_bottom {
  height: 15.3%;
  width: 100%;
  background-image: url("../images/background/a_background_bottom.png");
  background-size: 100% 100%;
}

#sun {
  background: url("../images/sun.png") no-repeat;
  position: absolute;
  z-index: 1;
  top: -30px;
  height: 201px;
  width: 201px;
  left: -2%;
}

.rotation {
  animation: rotation 30s;
}

@keyframes rotation {
  0% {
    transform: translateX(0) translateY(0);
  }
  100% {
    transform: translateX(-2000px) translateY(400px);
  }
}

.cloud {
  z-index: 2;
  position: absolute;
}

.cloud1 {
  width: 181px;
  height: 101px;
  left: -5%;
  top: 15%;
  background: url("../images/cloud1.png");
  animation: smallCloud 30s linear infinite;
}

.cloud2 {
  width: 301px;
  height: 140px;
  left: 15%;
  top: 2%;
  background: url("../images/cloud2.png");
  animation: largeCloud 40s linear infinite;
}

@keyframes smallCloud {
  0% {
    left: -5%;
  }
  100% {
    left: 80%;
  }
}

@keyframes largeCloud {
  0% {
    left: 5%;
  }
  100% {
    left: -20%;
  }
}