body {
  font-family: 'Roboto', sans-serif;
  text-align: center;
  margin: 0;
  padding: 0;
}

#game {
  display: flex;
  justify-content: center;
  align-items: center;
  padding-top: 10px;
}

/* Clouds */

#clouds {
  padding: 100px 0;
  background: #c9dbe9;
  background: -webkit-linear-gradient(top, #c9dbe9 0%, #fff 100%);
  background: -linear-gradient(top, #c9dbe9 0%, #fff 100%);
  background: -moz-linear-gradient(top, #c9dbe9 0%, #fff 100%);
  position: fixed;
  z-index: -1;
  width: 100%;
}

/*Time to finalise the cloud shape*/
.cloud {
  width: 200px;
  height: 60px;
  background: #fff;

  border-radius: 200px;
  -moz-border-radius: 200px;
  -webkit-border-radius: 200px;

  position: relative;
}

.cloud:before, .cloud:after {
  content: '';
  position: absolute;
  background: #fff;
  width: 100px;
  height: 80px;
  position: absolute;
  top: -15px;
  left: 10px;

  border-radius: 100px;
  -moz-border-radius: 100px;
  -webkit-border-radius: 100px;

  -webkit-transform: rotate(30deg);
  transform: rotate(30deg);
  -moz-transform: rotate(30deg);
}

.cloud:after {
  width: 120px;
  height: 120px;
  top: -55px;
  left: auto;
  right: 15px;
}

/*Time to animate*/
.x1 {
  -webkit-animation: moveclouds 15s linear 2;
  -moz-animation: moveclouds 15s linear 2;
  -o-animation: moveclouds 15s linear 2;
}

/*variable speed, opacity, and position of clouds for realistic effect*/
.x2 {
  left: 200px;

  -webkit-transform: scale(0.6);
  -moz-transform: scale(0.6);
  transform: scale(0.6);
  opacity: 0.6; /*opacity proportional to the size*/

  /*Speed will also be proportional to the size and opacity*/
  /*More the speed. Less the time in 's' = seconds*/
  -webkit-animation: moveclouds 25s linear 2;
  -moz-animation: moveclouds 25s linear 2;
  -o-animation: moveclouds 25s linear 2;
}

.x3 {
  left: 70%;
  top: -200px;

  -webkit-transform: scale(0.8);
  -moz-transform: scale(0.8);
  transform: scale(0.8);
  opacity: 0.8; /*opacity proportional to the size*/

  -webkit-animation: moveclouds 20s linear 2;
  -moz-animation: moveclouds 20s linear 2;
  -o-animation: moveclouds 20s linear 2;
}

.x4 {
  left: 470px;
  top: -250px;

  -webkit-transform: scale(0.75);
  -moz-transform: scale(0.75);
  transform: scale(0.75);
  opacity: 0.75; /*opacity proportional to the size*/

  -webkit-animation: moveclouds 18s linear 2;
  -moz-animation: moveclouds 18s linear 2;
  -o-animation: moveclouds 18s linear 2;
}

.x5 {
  left: -150px;
  top: -150px;

  -webkit-transform: scale(0.8);
  -moz-transform: scale(0.8);
  transform: scale(0.8);
  opacity: 0.8; /*opacity proportional to the size*/

  -webkit-animation: moveclouds 20s linear 2;
  -moz-animation: moveclouds 20s linear 2;
  -o-animation: moveclouds 20s linear 2;
}

@-webkit-keyframes moveclouds {
  0% {
    margin-left: 0;
  }
  100% {
    margin-left: 100%;
  }
}

@-moz-keyframes moveclouds {
  0% {
    margin-left: 0;
  }
  100% {
    margin-left: 100%;
  }
}

@-o-keyframes moveclouds {
  0% {
    margin-left: 0;
  }
  100% {
    margin-left: 100%;
  }
}