SOURCE

<div class="cssload-container">
	<div class="cssload-arc">
		<div class="cssload-arc-cube"></div>
	</div>
</div>

.cssload-container {
	position: relative;
	width: 195px;
	height: 195px;
	display:block;
	margin:49px auto;
	perspective: 975px;
		-o-perspective: 975px;
		-ms-perspective: 975px;
		-webkit-perspective: 975px;
		-moz-perspective: 975px;
	perspective: 975px;
		-o-perspective: 975px;
		-ms-perspective: 975px;
		-webkit-perspective: 975px;
		-moz-perspective: 975px;
	overflow: hidden;
}

.cube {
	position: absolute;
	bottom: 50%;
	left: 50%;
	width: 29px;
	height: 29px;
	margin-left: -15px;
	margin-top: 0;
}

.cube-2d {
	background-color: rgb(0,0,0);
}
.cssload-arc {
	position: absolute;
	bottom: 50%;
	left: 50%;
	margin-left: -68px;
	width: 136px;
	height: 68px;
	overflow: hidden;
}

.cssload-arc-cube {
	position: absolute;
	bottom: -68px;
	left: 50%;
	margin-left: -68px;
	width: 136px;
	height: 136px;
	border-style: solid;
	border-top-color: transparent;
	border-right-color: rgb(0,0,0);
	border-left-color: transparent;
	border-bottom-color: transparent;
	border-radius: 50%;
		-o-border-radius: 50%;
		-ms-border-radius: 50%;
		-webkit-border-radius: 50%;
		-moz-border-radius: 50%;
	box-sizing: border-box;
		-o-box-sizing: border-box;
		-ms-box-sizing: border-box;
		-webkit-box-sizing: border-box;
		-moz-box-sizing: border-box;
	animation: cssload-arc 2.3s ease-in-out infinite;
		-o-animation: cssload-arc 2.3s ease-in-out infinite;
		-ms-animation: cssload-arc 2.3s ease-in-out infinite;
		-webkit-animation: cssload-arc 2.3s ease-in-out infinite;
		-moz-animation: cssload-arc 2.3s ease-in-out infinite;
	transform: rotate(-200deg);
		-o-transform: rotate(-200deg);
		-ms-transform: rotate(-200deg);
		-webkit-transform: rotate(-200deg);
		-moz-transform: rotate(-200deg);
}

@keyframes cssload-arc {
	0% {
		border-width: 29px;
	}
	25% {
		border-width: 15px;
	}
	50% {
		transform: rotate(27deg);
		border-width: 29px;
	}
	75% {
		border-width: 15px;
	}
	100% {
		border-width: 29px;
	}
}

@-o-keyframes cssload-arc {
	0% {
		border-width: 29px;
	}
	25% {
		border-width: 15px;
	}
	50% {
		-o-transform: rotate(27deg);
		border-width: 29px;
	}
	75% {
		border-width: 15px;
	}
	100% {
		border-width: 29px;
	}
}

@-ms-keyframes cssload-arc {
	0% {
		border-width: 29px;
	}
	25% {
		border-width: 15px;
	}
	50% {
		-ms-transform: rotate(27deg);
		border-width: 29px;
	}
	75% {
		border-width: 15px;
	}
	100% {
		border-width: 29px;
	}
}

@-webkit-keyframes cssload-arc {
	0% {
		border-width: 29px;
	}
	25% {
		border-width: 15px;
	}
	50% {
		-webkit-transform: rotate(27deg);
		border-width: 29px;
	}
	75% {
		border-width: 15px;
	}
	100% {
		border-width: 29px;
	}
}

@-moz-keyframes cssload-arc {
	0% {
		border-width: 29px;
	}
	25% {
		border-width: 15px;
	}
	50% {
		-moz-transform: rotate(27deg);
		border-width: 29px;
	}
	75% {
		border-width: 15px;
	}
	100% {
		border-width: 29px;
	}
}