.fab{
  position: fixed;
  left: 26px;
  bottom: 26px;
  width: 64px;
  height: 64px;
  border-radius: 999px;
  background: #19c15b;
  display:grid;
  place-items:center;
  box-shadow: 0 18px 40px rgba(0,0,0,.55);
  z-index: 60;
  transition: transform .12s ease;
}
.fab:hover{ transform: translateY(-2px); }
.fab__icon{ font-size: 26px; color: #fff; }