.back-to-top 
{
    position: fixed;
    bottom: 2em;
    right: 0px;
    text-decoration: none;
    color: #000000;
    background-color: rgba(235, 235, 235, 0.80);
    font-size: 12px;
    padding: 1em;
    display: none;
		
}

.back-to-top:hover 
{    
    background-color: rgba(135, 135, 135, 0.50);
		
}