#wachat a {
  position: fixed;
  z-index: 9999;
  left: 0;
  float: right;
  bottom: 0%;
  cursor: pointer;
  min-width: 50px;
  max-width: 150px;
  color: #fff;
  text-align: center;
  padding: 8px;
  margin: 10px;
  background: #20b038;
  border-radius: 50%;
  -webkit-transition: All 0.5s ease;
  -moz-transition: All 0.5s ease;
  -o-transition: All 0.5s ease;
  -ms-transition: All 0.5s ease;
  transition: All 0.5s ease;
}

#wachat a img {
  width: 50px;
}