#myBtn {
  display: none;
  position: fixed;
  bottom: 20px;
  right: 20px;
  z-index: 999;
  border: solid;
  outline: none;
  background-color: gray;
  color: black;
  cursor: pointer;
  padding: 15px;
  border-radius: 10px;
  border-color: white;
}

#myBtn:hover {
  background-color: slategray;
}