css实现一个上下浮动的动画效果

css3实现一个上下浮动的动画效果（animation）

CSS 

@keyframes movepoint{from{top:50px}to{top:16px}}
.shade-button-point {
  display: inline-block;
  position: absolute;
  top: 50px;
  left: 30%;
  animation: movepoint 2s infinite;
  -webkit-animation: movepoint 2s infinite;
}

HTML

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