@-webkit-keyframes STAR-MOVES {
  from {
    background-position: 10% 10%;
  }
  to {
    background-position: 1500% 500%;
  }
}
@keyframes fadeMidground {
  0% {
    opacity: 0;
  }
  100% {
    opacity: 0.2;
  }
}
@keyframes fadeForeground {
  0% {
    opacity: 0;
  }
  100% {
    opacity: 0.3;
  }
}
#background {
  background: black url(../img/starfield-purp.jpg);
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 100;
  -webkit-animation-name: STAR-MOVES;
  -webkit-animation-duration: 400s;
  -webkit-animation-timing-function: linear;
  -webkit-animation-iteration-count: infinite;
}

#midground {
  background: url(../img/477265.jpg);
  opacity: 0.2;
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 200;
  -webkit-animation-name: STAR-MOVES;
  -webkit-animation-duration: 2000s;
  -webkit-animation-timing-function: linear;
  -webkit-animation-iteration-count: infinite;
  transition: opacity 3s;
  animation: fadeMidground 3s alternate infinite;
}

#foreground {
  background: url(https://earthsky.org/upl/2018/11/pleiades-seven-sisters-nov2019-e1572962425736.jpg);
  opacity: 0.1;
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 300;
  -webkit-animation-name: STAR-MOVES;
  -webkit-animation-duration: 1000s;
  -webkit-animation-timing-function: linear;
  -webkit-animation-iteration-count: infinite;
}