#scroll-to-top {
  display: inline-block;
  height: 50px;
  width: 50px;
  position: fixed;
  bottom: 20px;
  right: 20px;
  -webkit-box-shadow: 0 0 10px rgba(0, 0, 0, 0.05);
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.05);
  /* image replacement properties */
  overflow: hidden;
  z-index: 999;
  border-radius: 40px;
  text-indent: 100%;
  white-space: nowrap;
  background: #d08796 url(../image/top-arrow.svg) no-repeat center 50%;
  visibility: hidden; 
  opacity: 0.8; 
  -webkit-transition: opacity .3s ease-out, visibility .3s ease-out;
  transition: opacity .3s ease-out, visibility .3s ease-out;
}
#scroll-to-top.show {
  visibility: visible;
  opacity: .7;
}
#scroll-to-top:hover {
  opacity: 1;
}