button#backToTop {
	position:fixed; bottom:24px; right:20px; z-index:3; display:none; 
	background-color:rgba(250,250,250,0.75); color:#222; padding:20px 80px 40px; 
	border-radius:6px; border:1px solid #AAA; cursor:pointer; transition:.5s; 
}
button#backToTop:hover {background-color:rgba(50,50,50,0.75); color:#ddd;}

/* tablet(md), desktop(md,lg,xl) */
@media screen and (min-width:768px) {
	button#backToTop {border-radius:8px; font-size:200px; padding:20px 100px 40px;}  
}