.nav-top-btn{
  position:absolute;
  right:.7rem;
  top:calc(.55rem + var(--safe-top));
  z-index:3;
  width:2.55rem;
  height:2.55rem;
  border:1px solid rgba(0,0,0,.07);
  border-radius:999px;
  background:rgba(255,255,255,.93);
  color:#44464d;
  box-shadow:0 3px 12px rgba(0,0,0,.06);
  font-size:20px;
  font-weight:700;
  line-height:1;
  backdrop-filter:blur(18px);
  -webkit-backdrop-filter:blur(18px);
}
.nav-top-btn[hidden]{display:none!important}