.btn-wsp{
  position:fixed;
  width:60px;
  height:60px;
  line-height: 63px;
  bottom:25px;
  right:25px;
  background:#25d366;
  color:#FFF;
  border-radius:50px;
  text-align:center;
  font-size:35px;
  box-shadow: 0px 1px 10px rgba(0,0,0,0.3);
  z-index:100;
  transition: all 300ms ease;
}
.btn-wsp:hover{
  background: #20ba5a;
}
@media only screen and (min-width:320px) and (max-width:768px){
  .btn-wsp{
      width:63px;
      height:63px;
      line-height: 66px;
}
}