.all {
  width:100%;
  min-height:100%;

  position:relative;
}
.star {
  width:2px;
  height:2px; 
  background-color:rgba(255,255,255,1);
  border-radius:50%;
  background: radial-gradient(rgba(255,255,255,1), rgba(255,255,255,0));
  display:inline-block;
  position: absolute;
}
.nebuleuse {
  min-height:50%;
  height:50%;
  position: absolute;
  top:25%;
  background:rgba(255,255,255,0);
}
.pink {
  background: radial-gradient(rgba(255,255,255,1), rgba(255,255,255,0));
  width:3px;
  height:3px;
}
.yellow {
  background: radial-gradient(rgba(255,255,255,1), rgba(255,255,255,0));
  width:4px;
  height:4px;
}
.naine {
  width:5px;
  height:5px;
}
.soleil {
  width:6px;
  height:6px;
}
.novae {
  width:7px;
  height:7px;
}
.geante {
  width: 17px; 
  height: 17px;
  background: radial-gradient(rgba(255,255,255,0.7), rgba(255,255,255,0));
}
@keyframes mymove {
    to {top:100%;left: 0;}
}
.-- {
  animation-name: mymove;
  animation-duration: 2s;
  animation-iteration-count:infinite;
}