.back-to-top {
  color: #333333;
  display: inline-block;
  position: fixed;
  bottom: 30px;
  right: 20px;
  text-align: center;
  opacity: 0;
  -webkit-transition: opacity 2s;
  transition: opacity 2s;
  z-index: 100000000 !important;
}

@media (min-width: 992px) {
  .back-to-top {
    bottom: 100px;
    right: 20px;
  }
}

.back-to-top-icon {
  font-size: 35px;
  color: #ffffff;
  background: #333;
  padding: 15px;
  text-decoration: none;
}