css实现呼吸灯动效

先看效果：

实现原理：改变图片的透明度

代码：

 <div class="breath"></div>

.breath {
  width: 8%;
  height: 77%;
  position: absolute;
  right: 19px;
  top: 17px;
  background: url("../../assets/image/drugRight/BreathingLampL.png") no-repeat;
  background-size: 100% 100%;
  animation: breathLamp 2s alternate infinite;
}
@keyframes breathLamp{
  0%{
    opacity:.2;
  }
  100%{
    opacity:1;
  }
}