#back-to-top {
  background: #484848;
  border-radius: 100%;
  bottom: 25px;
  display: inline-block;
  height: 50px;
  opacity: 0;
  position: fixed;
  right: 20px;
  visibility: hidden;
  width: 50px;

  -webkit-box-shadow: 0 0 10px rgba(0, 0, 0, 0.05);
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.05);

  -webkit-transition: opacity 0.3s 0s, visibility 0s 0.3s;
  transition: opacity 0.3s 0s, visibility 0s 0.3s;
}

#back-to-top::after {
  color: #fff;
  content: '\f062';
  display: inline-block;
  font: normal normal normal 14px/1 FontAwesome;
  font-size: 2em;
  line-height: 47px;
  text-align: center;
  width: 50px;
}

#back-to-top.is-visible {
  opacity: 0.85;
  visibility: visible;
}

#back-to-top.reduce_opacity {
  opacity: 0.5;
}

#back-to-top:hover {
  opacity: 1;
  -webkit-transition: opacity 0.3s 0s, visibility 0s 0s;
  transition: opacity 0.3s 0s, visibility 0s 0s;
}
