.bbscrolltop-btn {
  position: fixed;
  bottom: 90px; /* stacked above the pt-quick-contact floating phone button */
  z-index: 1040;
  display: flex;
  align-items: center;
  justify-content: center;
  border: none;
  cursor: pointer;
  box-shadow: 0 6px 18px rgba(0,0,0,.25);
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity .25s ease, transform .25s ease, visibility .25s ease, background .2s ease;
}
.bbscrolltop-btn--right { right: 20px; }
.bbscrolltop-btn--left { left: 20px; bottom: 20px; }
.bbscrolltop-btn--visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}
.bbscrolltop-btn:hover {
  filter: brightness(0.92);
}
@media (max-width: 767px) {
  .bbscrolltop-btn { bottom: 78px; }
  .bbscrolltop-btn--left { bottom: 16px; }
}