箭头左右摇摆

.seat-sway {
  animation: sway 2s linear 0s infinite alternate;
  -moz-animation: sway 2s linear 0s infinite alternate;
  -webkit-animation: sway 2s linear 0s infinite alternate;
  -o-animation: sway 2s linear 0s infinite alternate;
  transform-origin: bottom;
}
@-webkit-keyframes sway {
  from {
    transform: rotate(30deg);
  }
  to {
    transform: rotate(-30deg);
  }
}
@-moz-keyframes sway {
  from {
    transform: rotate(30deg);
  }
  to {
    transform: rotate(-30deg);
  }
}
@-o-keyframes sway {
  from {
    transform: rotate(30deg);
  }
  to {
    transform: rotate(-30deg);
  }
}

@keyframes sway {
  from {
    transform: rotate(30deg);
  }
  to {
    transform: rotate(-30deg);
  }
}