.back-to-top {
		position: fixed;
		right: 400px;
		bottom: 20px;
		color: #4E4E4E;
		width: 40px;
		height: 40px;
		z-index: 2;
		display: none;
}
.back-to-top:before {
		content: "";
		display: block;
		width: 50px;
		height: 50px;
		border-radius: 20px;
		position: absolute;
		left: 0;
		top: 0;
		background: #EBEBEB;
		opacity: 0.8;
}
.back-to-top:after {
		content: "↑";
		font-size: 1.5rem;
		font-weight: bold;
		display: block;
		text-align: center;
		width: 50px;
		height: 50px;
		line-height: 50px;
		position: absolute;
		left: 0;
		top: 0;
}