.back-to-top {
width: 80px;
height: 40px;
position: fixed;
-webkit-transform: translate3d(0, 0, 0);
bottom: 150px;
right: 0px;
padding: 1em;
display: none;
z-index: 9999;
}

.back-to-top:hover {
background-color: rgba(135, 135, 135, 0.3);
border-radius: 5px;
cursor: pointer;
}