CSS3特效1 旋转的圆形

<div class="ball"></div>

.ball {

background-color: rgba(0,0,0,0);
border: 5px solid rgba(0,183,229,0.9);
opacity: .9;
border-top: 5px solid rgba(0,0,0,0);
border-left: 5px solid rgba(0,0,0,0);
border-radius: 150px;
box-shadow: 0 0 30px #2187e7;
width: 150px;
height: 150px;
margin: 0 auto;
position: absolute;
top:200px;
-webkit-animation: spin 1s infinite linear;

}

@-webkit-keyframes spin {
0% {
-webkit-transform: rotateX(45deg) rotate(0deg) ;
}

100% {
-webkit-transform: rotateX(45deg) rotate(360deg);
};
}