<style>
.sm::hover {visibility:visible;}

.sm_out {position:relative;}
.float_text {
  position:absolute;
  right:100px;
  width:100px;
  height:50px;
  margin-left:-50px;
  color:#000;
  /* 애니메이션 이름 */
  animation-name: paxmain;
  animation-duration:12s;
  /*animation-duration: leaner;*/
  animation-iteration-count:infinite;
  animation-direction:alternate-reverse;
  animation-fill-mode: forwards;
  }
/* 키프레임 이름 = 애니메이션 이름 */
@-webkit-keyframes paxmain {
  0% {
    left:100px;
  }
  100% {
    left:300px;
  }
}  
</style>