.container {
  position: relative;
  height: auto;
}

.scroll-buffer {
  height: 2000px;
}

.scroll-to-top-button {
  background: #222;
  color: white;
  text-decoration: none;
  position: fixed;
  bottom: 20px;
  right: 20px;
  padding: 10px;
  box-shadow: 0 10px 20px rgba(0,0,0,0.4);
  border-radius: 5px;
  opacity: 0;
  transition: .2s opacity ease-in-out;
}
.scroll-to-top-button
{
  z-index: 1;
}