.bck {
	position: fixed;
	bottom: 1rem;
	right: 1rem;
	background: #BB2463;
	border-radius: 50px;
	color: #fff;
	visibility: hidden;
	width: 50px;
	height: 50px;
	line-height: 50px;
	text-align:center;
	transition-property: all;
}

.main {
  height: 100vh;
  overflow-y: auto;
}


.bck:hover { background: #2C5F77;}

.bck.bck-on {visibility: visible;}

.fade{opacity: 0;}

.bck-on.fade{opacity: 1;}

.rightToLeft {right : -50px;}

.bck-on.rightToLeft{right: 1rem;}

.bottomToTop {bottom: -50px;}

.bck-on.bottomToTop {bottom:1rem;}

.bck-leftToRight {left: -50px;}

.bck-on.leftToRight {left:1rem;}

.topToBottom {top: -50px;}

.bck-on.topToBottom {top:1rem;}