.cd-top {
  display: inline-block;
  height: 40px;
  width: 40px;
  position: fixed;
  bottom:30px;
  right: 10px;
  box-shadow: 0 0 10px rgba(0,132,255, 0.05);
  border-radius:40px;
  /* image replacement properties */
  overflow: hidden;
  text-indent: 100%;
  white-space: nowrap;
  background: red url(/Design/1/cd-top-arrow.svg) no-repeat center 50%;
  visibility: hidden;
  opacity: 0;
  -webkit-transition: opacity .3s 0s, visibility 0s .3s;
  -moz-transition: opacity .3s 0s, visibility 0s .3s;
  transition: opacity .3s 0s, visibility 0s .3s;
}
.cd-top.cd-is-visible, .cd-top.cd-fade-out, .no-touch .cd-top:hover {
  -webkit-transition: opacity .3s 0s, visibility 0s 0s;
  -moz-transition: opacity .3s 0s, visibility 0s 0s;
  transition: opacity .3s 0s, visibility 0s 0s;
}
.cd-top.cd-is-visible {
  /* the button becomes visible */
  visibility: visible;
  opacity: 1;
}
.cd-top.cd-fade-out {
  /* if the user keeps scrolling down, the button is out of focus and becomes less visible */
  opacity: .5;
}
.cd-top:hover {
  background-color:red;
  opacity: 1;
}