#horizontal-scroll {
  height: 100%;
  background: url(../img/banner.jpg);
  -webkit-animation: backgroundScroll 600s linear infinite;
  animation: backgroundScroll 600s linear infinite;
}

@-webkit-keyframes backgroundScroll {
  from { background-position: 0 0;}
  to {background-position: 500% 0;}
}

@keyframes backgroundScroll {
  from { background-position: 0 0;}
  to {background-position: 500% 0;}
}