.fixed-btn {
  width: 250px;
  position: fixed;
  right: 0;
  bottom: 20px;
  display: block;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition:
    opacity 0.2s ease,
    visibility 0.2s ease;
  z-index: 10;
}
.fixed-btn.is-visible {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
}

@media screen and (max-width: 767px) {
  .fixed-btn {
    width: 33.33333vw;
    bottom: 2.66667vw;
  }
}