CSS3加载Loading动画

CSS代码：

.loadding-circle {
	display: inline-block;
    width: 30px;
    height: 30px;
    opacity: 0.75;
    margin: 0;
    background: none;
}
.loadding-circle {
    -webkit-animation: clockwise 600ms ease-out infinite;
    animation: clockwise 600ms ease-out infinite;
}
.loadding-circle .circle-cut {
    /* 
		The idea of animating inner circle is based on Polymer ("material") loading indicator 
		 by Keanu Lee https://blog.keanulee.com/2014/10/20/the-tale-of-three-spinners.html
	*/
    position: relative;
	display: inline-block;
    width: 20px;
    height: 30px;
    overflow: hidden;
}
.loadding-circle .circle-donut {
    position: absolute;
    top: 0;
    left: 0;
	display: inline-block;
    width: 30px;
    height: 30px;
    margin: 0;
    border: 2px solid #000;
    border-radius: 50%;
    border-left-color: transparent;
    border-bottom-color: transparent;
    background: none;
    -webkit-box-sizing: border-box;
    box-sizing: border-box;
}
.loadding-circle .circle-donut {
    -webkit-animation: donut-rotate 1200ms cubic-bezier(0.4, 0, 0.22, 1) infinite;
    animation: donut-rotate 1200ms cubic-bezier(0.4, 0, 0.22, 1) infinite;
}
@-webkit-keyframes clockwise {
    0% {
        -webkit-transform: rotate(0deg);
        transform: rotate(0deg);
    }
    100% {
        -webkit-transform: rotate(360deg);
        transform: rotate(360deg);
    }
}
@keyframes clockwise {
    0% {
        -webkit-transform: rotate(0deg);
        transform: rotate(0deg);
    }
    100% {
        -webkit-transform: rotate(360deg);
        transform: rotate(360deg);
    }
}
@-webkit-keyframes donut-rotate {
    0% {
        -webkit-transform: rotate(0);
        transform: rotate(0);
    }
    50% {
        -webkit-transform: rotate(-140deg);
        transform: rotate(-140deg);
    }
    100% {
        -webkit-transform: rotate(0);
        transform: rotate(0);
    }
}
@keyframes donut-rotate {
    0% {
        -webkit-transform: rotate(0);
        transform: rotate(0);
    }
    50% {
        -webkit-transform: rotate(-140deg);
        transform: rotate(-140deg);
    }
    100% {
        -webkit-transform: rotate(0);
        transform: rotate(0);
    }
}

HTML代码：

<div class="loadding-circle">
    <span class="circle-cut">
        <span class="circle-donut"></span>
    </span>
</div>