/* ==========================================================================
   nav.css — fixed dual header, nested dropdown menus, language picker,
   search-while-typing, mobile drawer.
   ========================================================================== */

.chrome { position: fixed; inset: 0 0 auto 0; z-index: 200; }

/* --- Primary bar ------------------------------------------------------ */
/* Both bars are explicitly layered. Each carries a backdrop-filter, which
   creates a stacking context, so without this the later-in-DOM .subbar paints
   over any dropdown that hangs out of .bar — and swallows the pointer with it. */
.bar {
  position: relative;
  z-index: 2;
  height: var(--header-h);
  display: flex;
  align-items: center;
  gap: clamp(16px, 2.5vw, 40px);
  padding-inline: var(--gutter);
  background: rgba(5,9,18,0.72);
  border-bottom: 1px solid var(--glass-stroke-1);
  backdrop-filter: blur(var(--glass-blur-xl)) saturate(var(--glass-saturate));
  -webkit-backdrop-filter: blur(var(--glass-blur-xl)) saturate(var(--glass-saturate));
}

.brand { display: flex; align-items: center; gap: var(--s-3); flex: none; }
/* The application's own mark (uploads/logo-v1-48.png), trimmed to its ink
   bounds — 35x26 native. Displayed at exactly that size so nothing is
   resampled on a 1x screen and nothing is stretched; srcset covers 2x/3x.
   Transparent background is preserved. */
.brand__mark { width: 35px; height: 26px; object-fit: contain; }
.brand__word { height: 15px; width: auto; object-fit: contain; opacity: 0.92; }
.brand:hover .brand__word { opacity: 1; }
.brand__sub {
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--fg-4);
  padding-left: var(--s-3);
  margin-left: var(--s-1);
  border-left: 1px solid var(--fg-5);
}

/* --- Menu ------------------------------------------------------------- */
.menu { display: flex; align-items: center; gap: var(--s-1); flex: 1; min-width: 0; }
.menu__item { position: relative; }
/* An invisible bridge across the visual gap between the bar and the panel, so
   moving the pointer down does not leave the item and close the menu. */
.menu__item[aria-expanded="true"]::after {
  content: "";
  position: absolute;
  top: 100%;
  left: 0;
  width: 100%;
  height: 14px;
}

.menu__link {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 9px 13px;
  border-radius: var(--r-sm);
  font-family: var(--font-ui);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: -0.005em;
  color: var(--fg-2);
  white-space: nowrap;
  transition: color var(--dur-2) var(--ease-out), background var(--dur-2) var(--ease-out);
}
.menu__link:hover,
.menu__item[aria-expanded="true"] > .menu__link { color: var(--fg-1); background: var(--glass-tint-1); }
.menu__link[aria-current="page"] { color: var(--accent); }
.menu__caret {
  width: 8px; height: 8px;
  border-right: 1.5px solid currentColor;
  border-bottom: 1.5px solid currentColor;
  transform: rotate(45deg) translateY(-1px);
  opacity: 0.55;
  transition: transform var(--dur-2) var(--ease-out);
}
.menu__item[aria-expanded="true"] .menu__caret { transform: rotate(225deg) translateY(-2px); opacity: 1; }

/* Dropdown panel — fade + 4px slide, 220ms (Aurix motion spec). */
.dropdown {
  position: absolute;
  top: calc(100% + 10px);
  left: -8px;
  z-index: 20;
  min-width: 620px;
  max-height: calc(100vh - var(--header-h) - 24px);
  overflow-y: auto;
  overscroll-behavior: contain;
  padding: var(--s-5);
  border-radius: var(--r-lg);
  background: rgba(8,13,26,0.90);
  border: 1px solid var(--glass-stroke-2);
  backdrop-filter: blur(var(--glass-blur-xl)) saturate(var(--glass-saturate));
  -webkit-backdrop-filter: blur(var(--glass-blur-xl)) saturate(var(--glass-saturate));
  box-shadow: var(--shadow-4), var(--glass-inner-lift);
  opacity: 0;
  transform: translateY(-4px);
  visibility: hidden;
  transition: opacity var(--dur-2) var(--ease-out), transform var(--dur-2) var(--ease-out), visibility var(--dur-2);
}
.menu__item[aria-expanded="true"] > .dropdown { opacity: 1; transform: none; visibility: visible; }
.dropdown--end { left: auto; right: -8px; }

.dropdown__cols { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: var(--s-5) var(--s-6); }
.dropdown__title {
  font-family: var(--font-mono);
  font-size: var(--t-overline);
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: var(--s-2);
  padding-bottom: 6px;
  border-bottom: 1px solid var(--fg-5);
}
.dropdown__link {
  display: block;
  padding: 4px 8px;
  margin-inline: -8px;
  border-radius: var(--r-xs);
  font-family: var(--font-ui);
  font-size: 13.5px;
  line-height: 1.25;
  color: var(--fg-2);
  transition: background var(--dur-1) var(--ease-out), color var(--dur-1) var(--ease-out);
}
.dropdown__link:hover { background: var(--glass-tint-2); color: var(--fg-1); }
.dropdown__link small { display: block; font-size: 11px; color: var(--fg-4); line-height: 1.3; margin-top: 1px; }

.dropdown__foot {
  margin-top: var(--s-5);
  padding-top: var(--s-3);
  border-top: 1px solid var(--fg-5);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--s-4);
}

/* --- Secondary bar --------------------------------------------------- */
.subbar {
  position: relative;
  z-index: 1;
  height: var(--subheader-h);
  display: flex;
  align-items: center;
  gap: var(--s-4);
  padding-inline: var(--gutter);
  background: rgba(5,9,18,0.55);
  border-bottom: 1px solid var(--glass-stroke-1);
  backdrop-filter: blur(var(--glass-blur-lg));
  -webkit-backdrop-filter: blur(var(--glass-blur-lg));
}

/* --- Search ---------------------------------------------------------- */
.search { position: relative; z-index: 1; flex: 1; max-width: 520px; }
.search__field {
  display: flex;
  align-items: center;
  gap: var(--s-3);
  height: 34px;
  padding-inline: var(--s-4);
  border-radius: var(--r-pill);
  background: var(--glass-tint-1);
  border: 1px solid var(--glass-stroke-1);
  transition: border-color var(--dur-2) var(--ease-out), background var(--dur-2) var(--ease-out);
}
.search__field:focus-within { border-color: var(--accent); background: var(--glass-tint-2); }
.search__icon { width: 15px; height: 15px; flex: none; stroke: var(--fg-4); fill: none; stroke-width: 1.75; }
.search__field:focus-within .search__icon { stroke: var(--accent); }
.search__input { flex: 1; min-width: 0; border: 0; background: none; outline: none; font-family: var(--font-ui); font-size: 13.5px; color: var(--fg-1); }
.search__input::placeholder { color: var(--fg-4); }
.search__kbd { font-family: var(--font-mono); font-size: 10px; letter-spacing: 0.1em; color: var(--fg-4); border: 1px solid var(--fg-5); border-radius: 4px; padding: 2px 5px; }

.search__results {
  position: absolute;
  top: calc(100% + 8px);
  left: 0; right: 0;
  max-height: min(62vh, 520px);
  overflow-y: auto;
  padding: var(--s-2);
  border-radius: var(--r-md);
  background: rgba(8,13,26,0.94);
  border: 1px solid var(--glass-stroke-2);
  backdrop-filter: blur(var(--glass-blur-xl));
  -webkit-backdrop-filter: blur(var(--glass-blur-xl));
  box-shadow: var(--shadow-4);
  display: none;
}
.search[data-open="true"] .search__results { display: block; }
.search__hit { display: block; padding: 9px 12px; border-radius: var(--r-xs); color: var(--fg-2); }
.search__hit:hover, .search__hit[data-active="true"] { background: var(--glass-tint-2); color: var(--fg-1); }
.search__hit-title { display: block; font-family: var(--font-ui); font-size: 14px; font-weight: 500; color: var(--fg-1); }
.search__hit-title mark { background: none; color: var(--accent); font-weight: 600; }
.search__hit-meta { display: block; font-family: var(--font-mono); font-size: 10px; letter-spacing: 0.16em; text-transform: uppercase; color: var(--fg-4); margin-top: 3px; }
.search__hit-snippet { display: block; font-size: 12.5px; color: var(--fg-3); line-height: 1.45; margin-top: 4px; }
.search__hit-snippet mark { background: none; color: var(--accent-soft); }
.search__section { padding: 10px 12px 4px; font-family: var(--font-mono); font-size: 10px; letter-spacing: 0.2em; text-transform: uppercase; color: var(--fg-4); }
.search__empty { padding: 18px 12px; font-size: 13.5px; color: var(--fg-3); }

/* --- Language picker ------------------------------------------------- */
.lang { position: relative; flex: none; }
.lang__toggle {
  display: flex;
  align-items: center;
  gap: var(--s-2);
  height: 32px;
  padding-inline: var(--s-3);
  border-radius: var(--r-pill);
  border: 1px solid var(--glass-stroke-1);
  background: var(--glass-tint-1);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--fg-2);
  transition: border-color var(--dur-2) var(--ease-out), color var(--dur-2) var(--ease-out);
}
.lang__toggle:hover, .lang[data-open="true"] .lang__toggle { border-color: var(--accent); color: var(--fg-1); }
.lang__globe { width: 14px; height: 14px; stroke: currentColor; fill: none; stroke-width: 1.6; }

.lang__menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  width: 208px;
  max-height: 60vh;
  overflow-y: auto;
  overscroll-behavior: contain;
  padding: var(--s-2);
  border-radius: var(--r-md);
  background: rgba(8,13,26,0.94);
  border: 1px solid var(--glass-stroke-2);
  backdrop-filter: blur(var(--glass-blur-xl));
  -webkit-backdrop-filter: blur(var(--glass-blur-xl));
  box-shadow: var(--shadow-4);
  display: none;
}
/* A fixed-height multi-column box lays its columns out sideways, so the picker
   scrolled horizontally through 82 languages. One column, scrolled vertically. */
.lang[data-open="true"] .lang__menu { display: flex; flex-direction: column; }
.lang__opt { display: block; padding: 7px 9px; border-radius: var(--r-xs); font-family: var(--font-ui); font-size: 13px; color: var(--fg-2); flex: none; }
.lang__opt:hover { background: var(--glass-tint-2); color: var(--fg-1); }
.lang__opt[aria-current="true"] { color: var(--accent); background: var(--glass-tint-1); }
.lang__note { padding: 8px 10px 10px; font-size: 11.5px; line-height: 1.45; color: var(--fg-4); border-bottom: 1px solid var(--fg-5); margin-bottom: var(--s-2); flex: none; }

/* --- Burger / drawer -------------------------------------------------- */
.burger { display: none; width: 40px; height: 40px; place-items: center; border-radius: var(--r-sm); border: 1px solid var(--glass-stroke-1); flex: none; }
.burger span { display: block; width: 18px; height: 1.5px; background: var(--fg-1); border-radius: 2px; transition: transform var(--dur-2) var(--ease-out), opacity var(--dur-2) var(--ease-out); }
.burger span + span { margin-top: 4px; }
/* Open state becomes an X so the control reads as a toggle, not a link. */
.burger[aria-expanded="true"] span:nth-child(1) { transform: translateY(5.5px) rotate(45deg); }
.burger[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.burger[aria-expanded="true"] span:nth-child(3) { transform: translateY(-5.5px) rotate(-45deg); }

.drawer {
  position: fixed;
  inset: var(--chrome-h) 0 0 0;
  z-index: 190;
  overflow-y: auto;
  overflow-x: hidden;
  overscroll-behavior: contain;
  padding: var(--s-6) var(--gutter) var(--s-24);
  background: rgba(5,9,18,0.97);
  backdrop-filter: blur(var(--glass-blur-xl));
  -webkit-backdrop-filter: blur(var(--glass-blur-xl));
  transform: translateY(-8px);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--dur-3) var(--ease-out), transform var(--dur-3) var(--ease-out), visibility var(--dur-3);
}
body[data-drawer="open"] .drawer { opacity: 1; transform: none; visibility: visible; }
body[data-drawer="open"] { overflow: hidden; }
.drawer__section + .drawer__section { margin-top: var(--s-8); padding-top: var(--s-6); border-top: 1px solid var(--fg-5); }
.drawer__head { display: block; font-family: var(--font-display); font-size: var(--t-h5); font-weight: 700; margin-bottom: var(--s-4); }
.drawer__grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: var(--s-5) var(--s-6); }
.drawer .dropdown__link { margin-inline: 0; }

/* Between 1024 and 1320 the six top-level items compress rather than collapsing:
   a horizontal dropdown menu is the desktop pattern and should survive a
   laptop-width window. */
@media (max-width: 1320px) {
  .bar { gap: clamp(12px, 1.6vw, 24px); }
  .menu__link { padding: 9px 9px; font-size: 13.5px; }
  .brand__sub { display: none; }
  .dropdown { min-width: min(560px, calc(100vw - 32px)); }
}
@media (max-width: 1024px) {
  /* Still a horizontal dropdown menu, just tighter and horizontally scrollable
     if the window is genuinely narrow. Collapsing to a hamburger on a desktop
     window hides the primary navigation from the people most likely to use it. */
  .bar { gap: var(--s-3); }
  .menu { overflow-x: auto; scrollbar-width: none; -ms-overflow-style: none; }
  .menu::-webkit-scrollbar { display: none; }
  .menu__link { padding: 9px 7px; font-size: 13px; }
  .dropdown { min-width: min(520px, calc(100vw - 24px)); }
  .dropdown, .dropdown--end { left: 0; right: auto; }
}
@media (max-width: 760px) {
  .menu { display: none; }
  .burger { display: grid; margin-left: auto; }
}
@media (max-width: 720px) {
  .search__kbd { display: none; }
  .subbar { gap: var(--s-2); }
}