.whats {
  position: fixed;
  bottom: 15px;
  right: 15px;
  z-index: 999;
}

.whats a {
  display: block;
  width: 40px;
  height: 40px;
  background: #2dcc70;
  border-radius: 50%;
  transition: background-color 0.2s ease;
}

.whats a:hover {
  background: #19924b;
}

.whats a img {
  width: 50%;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

@media only screen and (min-width: 768px) {
  .whats {
    bottom: 12px;
    right: 12px;
  }
  .whats a {
      width: 50px;
      height: 50px;
  }
}