html5实现图片转圈的动画效果――让页面动起来

<img src="images/circle.png" alt="" id="circle"/>@mixin ani-btnRotate{    @keyframes btnRotate{        from{transform: rotateZ(0);}        to{transform: rotateZ(360deg);}    }}@include ani-btnRotate;#circle{    position: absolute;    left: 50%;    width: REM(338);    height:  REM(338);    margin-top: REM(200);    margin-left: REM(-338/2);    transform-origin: center center ;    animation: btnRotate 1s 1s linear forwards;    }