.back-to-top {
  position: fixed;
  right: 33px;
  bottom: 200px;
  width: 70px;
  height: 70px;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
  z-index: 1000;
}
.back-to-top:hover {
  transform: scale(1.1);
}

.back-to-top.show {
  opacity: 1;
  visibility: visible;
}

.back-to-top img {
  width: 100%;
  height: auto;
}