.arrow {
  position: fixed;
  right: 20px;
  bottom: 20px;
  width: 50px;
  height: 50px;
  background-color: transparent;
  border-radius: 50%;
  cursor: pointer;
  opacity: 0.5;
  transition: opacity, transform 0.3s;
  display: none;
}

.arrow--visible {
  display: block;
}

.arrow:hover {
  transform: scale(1.1);
  opacity: 1;
}

@media screen and (max-width: 768px) {
  .arrow--visible {
    display: none;
  }
}