/* Site-wide hierarchical navigation */
:root {
  --nav-w: 300px;
}

.site-crumb {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0.55rem 1.5rem;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.04em;
  color: var(--muted);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.35rem 0.25rem;
  border-bottom: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.55);
}

.site-crumb a {
  color: var(--muted);
  text-decoration: none;
}

.site-crumb a:hover { color: var(--blue); }

.site-crumb .sep { opacity: 0.4; margin: 0 0.15rem; }

.site-crumb .here {
  color: var(--ink);
  font-weight: 500;
}

.site-nav-toggle {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 0.4rem 0.75rem;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  white-space: nowrap;
}

.site-nav-toggle:hover,
.site-nav-toggle[aria-expanded="true"] {
  border-color: var(--blue);
  color: var(--blue);
}

.site-nav-toggle .ico {
  width: 12px;
  height: 10px;
  display: inline-grid;
  gap: 2px;
}
.site-nav-toggle .ico i {
  display: block;
  height: 1.5px;
  background: currentColor;
}

/* Keep top links compact; drawer is primary hierarchy */
.site-header-actions {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  margin-left: auto;
}

.site-header .nav-links {
  display: none;
}

@media (min-width: 1100px) {
  .site-header .nav-links {
    display: flex;
    max-width: 48vw;
    overflow-x: auto;
  }
}

.site-nav-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(10, 14, 23, 0.35);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s;
  z-index: 90;
}

.site-nav-backdrop.open {
  opacity: 1;
  pointer-events: auto;
}

.site-nav-drawer {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  width: min(var(--nav-w), 92vw);
  background: #fff;
  border-right: 1px solid var(--line);
  z-index: 100;
  transform: translateX(-105%);
  transition: transform 0.22s ease;
  display: flex;
  flex-direction: column;
  box-shadow: none;
}

.site-nav-drawer.open {
  transform: translateX(0);
}

.site-nav-drawer-head {
  padding: 1.1rem 1.15rem 0.9rem;
  border-bottom: 1px solid var(--line);
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 0.75rem;
}

.site-nav-drawer-head .t {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1rem;
  line-height: 1.25;
}

.site-nav-drawer-head .s {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
  margin-top: 0.35rem;
}

.site-nav-close {
  border: 1px solid var(--line);
  background: var(--paper);
  width: 32px;
  height: 32px;
  cursor: pointer;
  font-size: 1.1rem;
  line-height: 1;
  color: var(--muted);
  flex-shrink: 0;
}

.site-nav-close:hover { color: var(--ink); border-color: var(--blue); }

.site-nav-tree {
  flex: 1;
  overflow-y: auto;
  padding: 0.75rem 0 1.5rem;
}

.site-nav-tree a {
  text-decoration: none;
  color: inherit;
}

.nav-home {
  display: block;
  padding: 0.55rem 1.15rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  color: var(--blue);
  border-bottom: 1px solid var(--line);
  margin-bottom: 0.35rem;
}

.nav-home:hover { background: var(--blue-soft); }

.nav-group {
  border-bottom: 1px solid #eef1f6;
}

.nav-group-btn {
  width: 100%;
  display: grid;
  grid-template-columns: 2rem 1fr auto;
  gap: 0.35rem;
  align-items: center;
  text-align: left;
  padding: 0.7rem 1.15rem;
  border: none;
  background: transparent;
  cursor: pointer;
  font-family: var(--font-body);
  color: var(--ink);
}

.nav-group-btn:hover { background: var(--paper); }

.nav-group-btn .num {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  color: var(--blue);
  letter-spacing: 0.04em;
}

.nav-group-btn .name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.92rem;
}

.nav-group-btn .chev {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--muted);
  transition: transform 0.15s;
}

.nav-group.open .nav-group-btn .chev {
  transform: rotate(90deg);
}

.nav-group.active-group > .nav-group-btn {
  background: var(--blue-soft);
}

.nav-children {
  display: none;
  padding: 0 0 0.55rem;
}

.nav-group.open .nav-children {
  display: block;
}

.nav-children a {
  display: grid;
  grid-template-columns: 2rem 1fr;
  gap: 0.35rem;
  padding: 0.4rem 1.15rem 0.4rem 1.15rem;
  font-size: 0.86rem;
  color: var(--ink-soft);
}

.nav-children a .dot {
  font-family: var(--font-mono);
  font-size: 0.6rem;
  color: var(--muted);
  padding-top: 0.2rem;
}

.nav-children a:hover {
  background: var(--paper);
  color: var(--blue);
}

.nav-children a.current {
  color: var(--blue);
  background: var(--blue-soft);
  font-weight: 600;
}

.nav-children a.current .dot { color: var(--blue); }

.site-nav-footer {
  padding: 0.75rem 1.15rem;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 0.62rem;
  letter-spacing: 0.06em;
  color: var(--muted);
}

body.nav-lock { overflow: hidden; }

/* Floating affordance on very small screens when header wraps */
@media (max-width: 520px) {
  .site-nav-toggle { order: 3; }
}