html, body {
  height: 100%;
  margin: 0;
  padding: 0;
}

html,
body {
  margin: 0;
  min-height: 100%;
  padding: 0;
}

body {
  background-color: steelblue;
  font-family: 'Helvetica Neue',sans-serif;
  font-size: 12px;
  overflow: hidden;
}
body header,
body article {
  padding: 0 1em;
}

article {
  -webkit-box-align: center;
  -webkit-align-items: center;
      -ms-flex-align: center;
          align-items: center;
  display: -webkit-box;
  display: -webkit-flex;
  display: -ms-flexbox;
  display: flex;
  height: 100%;
  -webkit-box-pack: center;
  -webkit-justify-content: center;
      -ms-flex-pack: center;
          justify-content: center;
  -webkit-box-flex: 1;
  -webkit-flex: 1 100%;
      -ms-flex: 1 100%;
          flex: 1 100%;
  -webkit-box-orient: horizontal;
  -webkit-box-direction: normal;
  -webkit-flex-direction: row;
      -ms-flex-direction: row;
          flex-direction: row;
}
article > img {
  margin-top: -15px;
}

.cloud {
  display: block;
}

@-webkit-keyframes fall {
  0% {
    top: 120%;
  }

  100% {
    top: -200px;
  }
}

@keyframes fall {
  0% {
    top: 120%;
  }

  100% {
    top: -200px;
  }
}
@-webkit-keyframes fall-3 {
  0% {
    top: 120%;
  }

  50% {
    top: -200px;
  }

  100% {
    top: -200px;
  }
}
@keyframes fall-3 {
  0% {
    top: 120%;
  }

  50% {
    top: -200px;
  }

  100% {
    top: -200px;
  }
}
.fall {
  -webkit-animation: fall linear 5s infinite;
          animation: fall linear 5s infinite;
  left: 10%;
  position: absolute;
  top: 0;
}

.cloud-2 {
  -webkit-animation-duration: 10s;
          animation-duration: 10s;
  left: 75%;
  width: 25px;
}

.cloud-3 {
  -webkit-animation-duration: 5s;
          animation-duration: 5s;
  -webkit-animation-name: fall-3;
          animation-name: fall-3;
  left: 60%;
  width: 300px;
}

/*
 * Hide only visually, but have it available for screen readers: h5bp.com/v
 */
.visuallyhidden {
  border: 0;
  clip: rect(0 0 0 0);
  height: 1px;
  margin: -1px;
  overflow: hidden;
  padding: 0;
  position: absolute;
  width: 1px;
}