微信小程序中使用wxss加载图片并实现动画效果

.weui-loading {
margin: 0 5px;
width: 20px;
height: 20px;
display: inline-block;
vertical-align: middle;
animation: a 1s steps(12) infinite;
background: transparent url(data:image/svg+xml;base64,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) no-repeat;
background-size: 100%;
background-image: '../../resources/icon_api.png';
}
@keyframes a {
0% {
-webkit-transform: rotate(0deg);
transform: rotate(0deg);
}
to {
-webkit-transform: rotate(1turn);
transform: rotate(1turn);
}
}