.back-to-top{
  background: url(../back-to-top.svg) no-repeat center center;
  bottom: 20px;
  cursor: pointer;
  display: none;
  height: 102px;
  position: fixed;
  right: 20px;
  opacity: 0.8;
  width: 102px;
  z-index: 300;
}

.show-btn {
  display: block;
}

.back-to-top:hover {
  opacity: 1;
}

@media (max-width: 768px) {
  .back-to-top{
    width: 50px;
    height: 50px;
  }
}