.whatsapp {
  position:fixed;
  width:60px;
  height:60px;
  bottom:40px;
  right:40px;
  background-color:#25d366;
  color:#FFF;
  border-radius:50px;
  text-align:center;
  font-size:30px;
  z-index:100;
  
  -webkit-transition: background .7s;
  -moz-transition: background .7s;
  -o-transition: background .7s;
  transition: background .7s;
}

.whatsapp:hover {
  background-color:#1f5b63;
}

.fa-whatsapp {
  margin-top:10px;
  color:#FFF;
}

.fa-whatsapp:hover {
  color:#FFF;
}