.to-top-btn {
	background-color: #FFF;
	border-radius: 4px;
	bottom: 53px;
	box-shadow: 0 0 3px #333;
	display: block;
	height: 34px;
	left: 12px;
	opacity: 0.7;
	position: fixed;
	transition:opacity .3s linear, transform .3s linear;
	width: 34px;
	z-index: 10;
}
.to-top-btn::after {
	border: 3px solid #444;
	border-right-width: 0;
	border-bottom-width: 0;
	content: '';
	height: 10px;
	left: 50%;
	position: absolute;
	top: 14px;
	transform: translateX(-50%) rotate(45deg);
	width: 10px;
}
.to-top-btn:not(.active){opacity:0; transform:scale(0)}
.to-top-btn:focus,
.to-top-btn:hover,
.to-top-btn:active{opacity:1}

@media(min-width:768px){
	.to-top-btn{width:40px;height:40px}
	.to-top-btn::after {top: 17px;}
}