#bg {
  position: absolute;
  top: 0;
  left: 392px;
  width: 588px;
  height: 500px;
  
  z-index: 1;
}


body.bg0 #bg {
  background: url('../img/keyvisual.png') left top no-repeat;
}

body.bg1 #bg {
  background: url('../img/kv/2.png') left top no-repeat;
}

body.bg2 #bg {
  background: url('../img/kv/3.png') left top no-repeat;
}

body.bg3 #bg {
  background: url('../img/kv/4.png') left top no-repeat;
}

body.bg4 #bg {
  background: url('../img/kv/5.png') left top no-repeat;
}