純粋な CSS を使用して単純な読み込みアニメーション効果を実現します (コード例)

<div id="container">
	<div class="load-line rotate-0">
		<span class="left"></span>
		<span class="right"></span>
	</div>
	<div class="load-line rotate-30">
		<span class="left"></span>
		<span class="right"></span>
	</div>
	<div class="load-line rotate-60">
		<span class="left"></span>
		<span class="right"></span>
	</div>
	<div class="load-line rotate-90">
		<span class="left"></span>
		<span class="right"></span>
	</div>
	<div class="load-line rotate-120">
		<span class="left"></span>
		<span class="right"></span>
	</div>
	<div class="load-line rotate-150">
		<span class="left"></span>
		<span class="right"></span>
	</div>
	<div id="circle-center"></div>
</div>

#container, #circle-center {
	background: grey;
}
#container {
	position: relative;
	width: 600px;
	height: 300px;
}
#circle-center {
	position: absolute;
	top: 100px;
	left: 250px;
	width: 100px;
	height: 100px;
	border-radius: 100px;
}
.load-line {
	position: absolute;
	top: 150px;
	left: 200px;
	width: 200px;
	height: 13px;
}
.load-line > span {
	display: inline-block;
	width: 50%;
	height: 100%;
	border-radius: 20px;
	background: white;
}
.left {
	float: left;
}
.right {
	float: right;
}
.rotate-0 {
	transform: rotate(0);
}
.rotate-0 > .left {
	animation: load-effect 1.2s linear 0s infinite;
}
.rotate-0 > .right {
	animation: load-effect 1.2s linear 0.6s infinite;
}
.rotate-30 {
	transform: rotate(30deg);
}
.rotate-30 > .left {
	animation: load-effect 1.2s linear 0.1s infinite;
}
.rotate-30 > .right {
	animation: load-effect 1.2s linear 0.7s infinite;
}
.rotate-60 {
	transform: rotate(60deg);
}
.rotate-60 > .left {
	animation: load-effect 1.2s linear 0.2s infinite;
}
.rotate-60 > .right {
	animation: load-effect 1.2s linear 0.8s infinite;
}
.rotate-90 {
	transform: rotate(90deg);
}
.rotate-90 > .left {
	animation: load-effect 1.2s linear 0.3s infinite;
}
.rotate-90 > .right {
	animation: load-effect 1.2s linear 0.9s infinite;
}
.rotate-120 {
	transform: rotate(120deg);
}
.rotate-120 > .left {
	animation: load-effect 1.2s linear 0.4s infinite;
}
.rotate-120 > .right {
	animation: load-effect 1.2s linear 1.0s infinite;
}
.rotate-150 {
	transform: rotate(150deg);
}
.rotate-150 > .left {
	animation: load-effect 1.2s linear 0.5s infinite;
}
.rotate-150 > .right {
	animation: load-effect 1.2s linear 1.1s infinite;
}
@keyframes load-effect {
	0% {
		opacity: 0;
	}
	100% {
		opacity: 1;
	}
}