.ao-nav {
  --ao-bg: #fff;
  --ao-text: #444;
  --ao-muted: #999;
  --ao-border: #eee;
  --ao-accent: #3354aa;
  color: var(--ao-text);
  font-family: inherit;
  font-size: 14px;
  line-height: 1.6;
  box-sizing: border-box;
  text-align: left;
  min-width: 0;
  margin: 0 0 24px;
}
.ao-nav *, .ao-nav *::before, .ao-nav *::after { box-sizing: border-box; }
/* Reserve the original space; only the opaque directory follows the viewport. */
.ao-slot { display: block; width: 100%; margin: 0; padding: 0; pointer-events: none; }
.ao-nav[data-placement="sidebar"] {
  position: fixed;
  margin: 0;
  padding-bottom: 10px;
  background: var(--ao-bg);
  z-index: 50;
}
.ao-nav[data-placement="sidebar"] .ao-tree { max-height: max(60px, min(45dvh, calc(100dvh - var(--ao-offset, 80px) - 140px))); }
.ao-nav[data-placement="sidebar"]::before {
  content: '';
  position: absolute;
  inset: -10px -12px -2px;
  z-index: -1;
  pointer-events: none;
  background: var(--ao-bg);
  border: 1px solid #0000000d;
  border-radius: 4px;
  box-shadow: 0 2px 8px #0000000d, 0 1px 2px #00000006;
  opacity: 0;
  transition: opacity .16s ease;
}
.ao-nav[data-placement="sidebar"].ao-overlapping::before { opacity: 1; }
.ao-nav .ao-tree { overflow-anchor: none; }
.ao-nav .ao-panel { margin: 0; padding: 0; border: 0; border-radius: 0; background: transparent; overflow: hidden; box-shadow: none; }
.ao-nav .ao-summary { display: flex; align-items: center; gap: 10px; margin: 0; padding: 0 0 8px; cursor: pointer; color: var(--ao-text); font: 700 16px/1.4 "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Microsoft Yahei", sans-serif; list-style: none; }
.ao-nav .ao-summary::-webkit-details-marker { display: none; }
.ao-nav .ao-summary::after { content: '+'; margin-left: auto; color: var(--ao-muted); font-size: 14px; font-weight: 400; }
.ao-nav .ao-panel[open] > .ao-summary::after { content: '−'; }
.ao-nav .ao-tree { max-height: calc(100dvh - var(--ao-offset, 80px) - 80px); overflow-y: auto; overscroll-behavior: contain; scrollbar-width: thin; margin: 0; padding: 0; }
.ao-nav ol { list-style: none; }
.ao-nav .ao-tree ol { margin: 0; padding: 0 0 0 14px; border: 0; }
.ao-nav .ao-tree li { margin: 0; padding: 0; list-style: none; border: 0; background: none; }
.ao-nav .ao-tree li::before, .ao-nav .ao-tree li::after { content: none; }
.ao-nav .ao-tree a { display: block; margin: 0; padding: 1px 0; border: 0; border-radius: 0; color: var(--ao-accent); background: transparent; text-decoration: none; font-size: 14px; font-weight: 400; line-height: 1.45; overflow-wrap: anywhere; box-shadow: none; }
.ao-nav .ao-tree a:hover { color: var(--ao-text); text-decoration: underline; }
.ao-nav .ao-tree a[aria-current="location"] { color: var(--ao-text); background: transparent; font-weight: 700; box-shadow: none; }
.ao-nav a:focus-visible, .ao-nav summary:focus-visible { outline: 2px solid var(--ao-accent); outline-offset: -2px; }
.ao-nav[data-placement="floating"], .ao-nav[data-placement="mobile"] { position: fixed; right: 20px; bottom: 20px; z-index: 1000; width: 260px; max-width: calc(100vw - 32px); margin: 0; }
.ao-nav[data-placement="floating"] .ao-panel, .ao-nav[data-placement="mobile"] .ao-panel { border: 1px solid var(--ao-border); background: var(--ao-bg); }
.ao-nav[data-placement="floating"] .ao-summary, .ao-nav[data-placement="mobile"] .ao-summary { padding: 12px 14px; font-size: 14px; }
.ao-nav[data-placement="floating"] .ao-tree, .ao-nav[data-placement="mobile"] .ao-tree { padding: 0 8px 10px; }
.ao-nav[data-placement="floating"] .ao-tree { max-height: 55dvh; }
.ao-nav[data-placement="mobile"] { left: 16px; right: 16px; bottom: max(12px, env(safe-area-inset-bottom)); width: auto; }
.ao-nav[data-placement="mobile"] .ao-tree { max-height: 50dvh; }
.ao-nav[data-placement="mobile"] .ao-tree a { min-height: 32px; display: flex; align-items: center; }
@media print {
  .ao-nav { display: none !important; }
  .ao-slot { display: none; }
}
@media (prefers-reduced-motion: reduce) { .ao-nav[data-placement="sidebar"]::before { transition: none; } }