.pagetop {
  position: fixed;
  right: 20px;
  bottom: 20px;
  width: 40px;
  height: 40px;
  display: flex;
  justify-content: center;
  align-items: center;
  background: rgba(76,76,52,0.80);
  color: #fff;
  font-size: 8px;
  border-radius: 50%;
  text-decoration: none;
  opacity: 0;
  transform: translateY(50px);
  pointer-events: none;
  transition: opacity .3s ease, transform .3s ease;
  z-index: 1;
}
.pagetop.is-show {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}