/* Configurable Back-to-Top button */
#pf-backtotop{
  position: fixed;
  right: var(--pf-btt-right, 20px);
  bottom: var(--pf-btt-bottom, 20px);
  width: var(--pf-btt-size, 48px); height: var(--pf-btt-size, 48px);
  border-radius: 9999px;
  border: 1px solid rgba(0,0,0,.08);
  background: rgba(255,255,255,.98);
  box-shadow: 0 4px 12px rgba(0,0,0,.12);
  display: grid; place-items: center;
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transition: opacity .18s ease, transform .18s ease, background-color .18s ease;
  z-index: 99999;
}
#pf-backtotop svg{ fill: #111; display:block; }
#pf-backtotop img{ display:block; width:auto; height:auto; }
#pf-backtotop.show{ opacity: 1; pointer-events: auto; }
#pf-backtotop:hover{ transform: translateY(-2px); }
@media (prefers-color-scheme: dark){
  #pf-backtotop{ background: rgba(20,20,20,.92); border-color: rgba(255,255,255,.08); }
  #pf-backtotop svg{ fill: #f5f5f5; }
}
@media (prefers-reduced-motion: reduce){
  #pf-backtotop{ transition: none; }
}