html,
body {
  background-color: #010c0d;
  height: 100%;
  margin: 0;
  overflow: hidden;
}

body {
  padding: 50px 0;
}

.axis {
  background-color: rgba(255, 255, 255, 0.2);
  position: absolute;
  z-index: 100;
}

.planet {
  background-size: cover;
  left: 50%;
  position: absolute;
  top: 50%;
}

#background {
  background-image: url("http://www.alienresearchcorp.com/space/hd-wallpapers/amazing/img/l/moment-in-space-cvi.jpg");
  background-repeat: no-repeat;
  background-size: cover;
  bottom: -20%;
  left: -10%;
  position: absolute;
  right: -10%;
  top: -20%;
}

#x-axis {
  bottom: -50%;
  left: 50%;
  top: -50%;
  width: 1px;
}

#y-axis {
  left: 0;
  top: 50%;
  right: 0;
  height: 1px;
}

#planet-1 {
  margin: -75px 0 0 -75px;
  height: 150px;
  width: 150px;
  background-image: url("http://th02.deviantart.net/fs71/PRE/i/2012/337/3/6/planet_png_by_phip_phantom-d5mwylq.png");
  z-index: 20;
}

#planet-2 {
  margin: -100px 0 0 -100px;
  height: 200px;
  width: 200px;
  background-image: url("http://fc04.deviantart.net/fs71/i/2013/070/e/d/ice_planet___kronos_by_khrymsyn-d5xqmnm.png");
  z-index: 10;
}