.loop{
  width: 100%;
  height : 243px;
  /*?????????*/
  background : url(../img_common/kodou2.png) center center / auto auto repeat-x scroll padding-box border-box transparent;
  animation: bgloop 20s linear infinite;
/*?b????????D??????l??Ainfinite??c??*/

}
@keyframes bgloop {
  from {
  background-position: 0 0;
}
to {
  background-position: -1000px 0;
/*-1000px????????????????????l*/
  }
}