* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
#btn-mas {
  display: none;
}
.container_whatsapp {
  position: fixed;
  bottom: 20px;
  left: 20px;
  z-index: 999;
}
.redes a {
  display: block;
  text-decoration: none;
  background: #37a645;
  color: #fff;
  width: auto;
  height: auto;
  line-height: 10px;
  text-align: center;
  border-radius: 5%;
  padding: 10px 10px;
  box-shadow: 0px 1px 10px rgba(0, 0, 0, 0.4);
  transition: all 500ms ease;
  font-size: 16px;
}
.redes a:hover {
  background: #fff;
  color: #37a645;
}
.redes a {
  margin-bottom: -15px;
  opacity: 0;
  visibility: hidden;
}

#btn-mas:checked ~ .redes a {
  margin-bottom: 10px;
  opacity: 1;
  visibility: visible;
}
.btn-mas label {
  display: block;
  text-decoration: none;
  cursor: pointer;
  background: #37a645;
  color: #fff;
  width: 65px;
  height: 65px;
  line-height: 65px;
  font-size: 30px;
  text-align: center;
  border-radius: 50%;
  box-shadow: 0px 1px 10px rgba(0, 0, 0, 0.4);
  transition: all 500ms ease;
}
#btn-mas:checked ~ .btn-mas label {
  transform: rotate(135deg);
  width: 65px;
  height: 65px;
  font-size: 30px;
}