.boton-flotante {
  position: fixed;
  bottom: 20px;
  right: 20px;
  z-index: 9999;
}

.boton-flotante a {
  display: block;
  background-color: #ffffff;
  width: 50px;
  height: auto;
  background: #000;
  border-radius: 50%;
  text-align: center;
  line-height: 50px;
  text-decoration: none;
  color: #fff;
  font-size: 24px;
}

.boton-flotante img {
  width: 300px;
  height: auto;
  background-color: #ffffff;
}