#hcfcb-button {
  position: fixed;
  z-index: 9999;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  border-radius: 999px;
  transition: transform .15s ease, box-shadow .15s ease, opacity .15s ease;
}
#hcfcb-button svg {
  width: 52%;
  height: 52%;
  display: block;
}
#hcfcb-button:active { transform: scale(0.96); }
#hcfcb-button.hcfcb-shadow { box-shadow: 0 8px 24px rgba(0,0,0,.18); }
@media (pointer:fine) {
  #hcfcb-button:hover { transform: translateY(-1px); }
}