/* The shared page control stays reachable while reading, including on phones. */
.back-to-top {
  position: fixed;
  right: max(16px, env(safe-area-inset-right));
  bottom: max(16px, env(safe-area-inset-bottom));
  z-index: 25;
  display: grid;
  place-items: center;
  width: 48px;
  height: 48px;
  padding: 0;
  border: 1px solid var(--paper);
  border-radius: 50%;
  background: var(--action);
  color: #fff;
  box-shadow: 0 4px 18px #0003;
  cursor: pointer;
}
.back-to-top[hidden] { display: none; }
.back-to-top:hover { background: var(--action-hover); }
.back-to-top:focus-visible { outline: 3px solid var(--ink); outline-offset: 3px; }
#page-top:focus { outline: none; }
@media print { .back-to-top { display: none; } }