.poo-fixed-back-wrap{
  position:fixed;
  left:50%;
  transform:translateX(-50%);
  bottom:calc(16px + env(safe-area-inset-bottom));
  z-index:99999;
  max-width:calc(100% - 28px);
}

.poo-fixed-back-btn{
  display:inline-block;
  padding:12px 16px;
  border-radius:14px;
  font-weight:900;
  box-shadow:0 10px 24px rgba(0,0,0,.18);
}

.poo-fixed-back-wrap .poo-fixed-back-btn{
  background:#111827;
  color:#fff;
  border:1px solid rgba(255,255,255,.18);
}