#btn-back-to-top {
  position: fixed;
  bottom: 40px;
  right: 40px;
  display: none;
}
#btn-on-top {
  position: fixed;
  top: 40px;
  left: 40px;
  
}


.facebook{
    display:block;
    width:60px;
    height:60px;
    background:white;
    color:black;
    font-weight:bold;
    font-size:1.5rem;
    border-radius:50%;
    padding:10px 15px;
    margin-top:10px;
    line-height:2.5rem;
}