html5怎样做出图片转圈的动画效果

<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;

    }