/* ==========================================================================
   MEDLINE — LAYER 4: NAVIGATION
   Header styles 1–3, mega menu, mobile drawer, breadcrumb, pagination, tabs.
   Semantic tokens only.
   ========================================================================== */

/* --- Header shell -------------------------------------------------------
   Style 1 floating glass · Style 2 solid bar · Style 3 transparent-on-hero
   All three share this shell; the modifier changes surface + geometry.   */

.hdr { position: sticky; top: 0; z-index: var(--z-sticky); }

.hdr__utility {
  display: flex; align-items: center; justify-content: space-between;
  gap: var(--sp-4);
  padding: var(--sp-2) var(--sp-4);
  font-size: var(--fs-caption);
  color: var(--text-muted);
  border-bottom: 1px solid var(--border-subtle);
}
.hdr__utility a { color: inherit; }
.hdr__utility a:hover { color: var(--text-strong); }

.hdr__bar {
  display: flex; align-items: center; gap: var(--sp-6);
  padding: var(--sp-3) var(--sp-4);
  min-height: 68px;
}

.hdr__brand { display: flex; align-items: center; gap: var(--sp-3); min-width: max-content; }
.hdr__mark {
  width: 40px; height: 40px; border-radius: var(--r-sm);
  background: var(--accent); color: var(--accent-ink);
  display: grid; place-items: center;
  font-weight: var(--fw-black); font-size: var(--fs-lead);
}
.hdr__name { display: block; font-size: var(--fs-label); font-weight: var(--fw-black); letter-spacing: .12em; color: var(--text-strong); line-height: 1.2; }
.hdr__tag  { display: block; font-size: 9px; letter-spacing: .24em; color: var(--text-muted); }

.hdr__nav { display: flex; align-items: center; gap: var(--sp-2); flex: 1; justify-content: center; }
.hdr__actions { display: flex; align-items: center; gap: var(--sp-2); margin-inline-start: auto; }

.hdr__link {
  display: inline-flex; align-items: center; gap: var(--sp-1);
  min-height: var(--tap-min);
  padding-inline: var(--sp-3);
  border-radius: var(--r-sm);
  font-size: var(--fs-label); font-weight: var(--fw-semi);
  color: var(--text-muted);
  background: none; border: 0; cursor: pointer;
  transition: color var(--dur-base) var(--ease-out), background var(--dur-base) var(--ease-out);
}
.hdr__link:hover,
.hdr__link[aria-expanded="true"] { color: var(--text-strong); background: var(--surface-3); }
.hdr__link[aria-current="page"] { color: var(--accent); }
.hdr__caret { transition: transform var(--dur-base) var(--ease-out); font-size: 9px; }
.hdr__link[aria-expanded="true"] .hdr__caret { transform: rotate(180deg); }

/* Style 1 — floating glass card */
.hdr--glass { top: var(--sp-2); }
.hdr--glass .hdr__inner {
  width: min(var(--container), calc(100% - var(--sp-4)));
  margin-inline: auto;
  border-radius: var(--r-md);
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  box-shadow: var(--shadow-glass);
  overflow: hidden;
}
@supports (backdrop-filter: blur(1px)) {
  .hdr--glass .hdr__inner { backdrop-filter: blur(var(--glass-blur)) saturate(160%);
                            -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(160%); }
}

/* Style 2 — solid edge-to-edge bar */
.hdr--solid .hdr__inner { background: var(--surface-1); border-bottom: 1px solid var(--border); }
.hdr--solid .hdr__bar,
.hdr--solid .hdr__utility { width: min(var(--container), calc(100% - var(--sp-8))); margin-inline: auto; }

/* Style 3 — transparent over a hero, solidifies on scroll via [data-stuck] */
.hdr--transparent .hdr__inner {
  background: transparent; border-bottom: 1px solid transparent;
  transition: background var(--dur-slow) var(--ease-out), border-color var(--dur-slow) var(--ease-out);
}
.hdr--transparent .hdr__bar { width: min(var(--container), calc(100% - var(--sp-8))); margin-inline: auto; }
.hdr--transparent[data-stuck="true"] .hdr__inner {
  background: var(--glass-bg); border-bottom-color: var(--border);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
}

/* --- Mega menu ---------------------------------------------------------- */

.mega {
  position: absolute; left: 50%; transform: translateX(-50%) translateY(-6px);
  top: calc(100% - var(--sp-2));
  width: min(var(--container), calc(100vw - var(--sp-8)));
  padding: var(--sp-8);
  background: var(--surface-overlay);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  box-shadow: var(--shadow-overlay);
  opacity: 0; visibility: hidden; pointer-events: none;
  transition: opacity var(--dur-base) var(--ease-out),
              transform var(--dur-base) var(--ease-out),
              visibility var(--dur-base);
}
.mega[data-open="true"] { opacity: 1; visibility: visible; pointer-events: auto; transform: translateX(-50%) translateY(0); }

.mega__grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--sp-6); }
.mega__col-title {
  font-size: var(--fs-eyebrow); text-transform: uppercase; letter-spacing: var(--ls-eyebrow);
  font-weight: var(--fw-black); color: var(--text-subtle);
  margin: 0 0 var(--sp-3);
}
.mega__item {
  display: flex; gap: var(--sp-3); align-items: flex-start;
  padding: var(--sp-2) var(--sp-3);
  border-radius: var(--r-sm);
  transition: background var(--dur-base) var(--ease-out);
}
.mega__item:hover { background: var(--surface-3); }
.mega__item b { display: block; font-size: var(--fs-label); color: var(--text-strong); font-weight: var(--fw-bold); }
.mega__item small { display: block; font-size: var(--fs-caption); color: var(--text-muted); }
.mega__ico {
  width: 34px; height: 34px; flex: none;
  border-radius: var(--r-sm);
  display: grid; place-items: center;
  background: var(--accent-soft); color: var(--accent-soft-ink);
}
.mega__feature { grid-column: span 1; padding: var(--sp-6); border-radius: var(--r-md); background: var(--tint-blue); color: var(--tint-blue-ink); }
.mega__footer {
  display: flex; flex-wrap: wrap; gap: var(--sp-4); justify-content: space-between; align-items: center;
  margin-top: var(--sp-6); padding-top: var(--sp-4);
  border-top: 1px solid var(--border-subtle);
  font-size: var(--fs-caption); color: var(--text-muted);
}

/* --- Mobile drawer ------------------------------------------------------ */

.drawer-scrim {
  position: fixed; inset: 0; z-index: var(--z-drawer);
  background: var(--surface-scrim);
  opacity: 0; visibility: hidden;
  transition: opacity var(--dur-slow) var(--ease-out), visibility var(--dur-slow);
}
.drawer-scrim[data-open="true"] { opacity: 1; visibility: visible; }

.drawer {
  position: fixed; inset-block: 0; inset-inline-end: 0;
  z-index: calc(var(--z-drawer) + 1);
  width: min(400px, 88vw);
  display: flex; flex-direction: column;
  background: var(--surface-overlay);
  border-inline-start: 1px solid var(--border);
  box-shadow: var(--shadow-overlay);
  transform: translateX(100%);
  transition: transform var(--dur-slow) var(--ease-out);
  overscroll-behavior: contain;
}
[dir="rtl"] .drawer { transform: translateX(-100%); }
.drawer[data-open="true"] { transform: translateX(0); }

.drawer__head {
  display: flex; align-items: center; justify-content: space-between;
  gap: var(--sp-4);
  padding: var(--sp-4);
  border-bottom: 1px solid var(--border);
}
.drawer__body { flex: 1; overflow-y: auto; padding: var(--sp-4); }
.drawer__foot { padding: var(--sp-4); border-top: 1px solid var(--border); display: grid; gap: var(--sp-2); }

.drawer__link {
  display: flex; align-items: center; justify-content: space-between;
  width: 100%; min-height: var(--tap-min);
  padding: var(--sp-3);
  border: 0; background: none; cursor: pointer;
  border-radius: var(--r-sm);
  font-size: var(--fs-body); font-weight: var(--fw-semi);
  color: var(--text-strong); text-align: start;
}
.drawer__link:hover { background: var(--surface-3); }
.drawer__sub { display: none; padding-inline-start: var(--sp-3); margin-bottom: var(--sp-2); }
.drawer__link[aria-expanded="true"] + .drawer__sub { display: block; }
.drawer__sub a {
  display: block; min-height: var(--tap-min);
  padding: var(--sp-3);
  font-size: var(--fs-sm); color: var(--text-muted);
  border-inline-start: 2px solid var(--border);
}
.drawer__sub a:hover { color: var(--accent); border-color: var(--accent); }

/* --- Breadcrumb --------------------------------------------------------- */

.crumbs { display: flex; flex-wrap: wrap; align-items: center; gap: var(--sp-2); font-size: var(--fs-caption); }
.crumbs ol { display: contents; list-style: none; margin: 0; padding: 0; }
.crumbs li { display: flex; align-items: center; gap: var(--sp-2); color: var(--text-muted); }
.crumbs li + li::before { content: "/"; color: var(--text-subtle); }
.crumbs a:hover { color: var(--accent); text-decoration: underline; text-underline-offset: 3px; }
.crumbs [aria-current="page"] { color: var(--text-strong); font-weight: var(--fw-semi); }

/* --- Pagination --------------------------------------------------------- */

.pager { display: flex; flex-wrap: wrap; align-items: center; justify-content: center; gap: var(--sp-2); }
.pager__item {
  min-width: var(--tap-min); min-height: var(--tap-min);
  display: inline-grid; place-items: center;
  padding-inline: var(--sp-3);
  border: 1px solid var(--border); border-radius: var(--r-sm);
  background: var(--surface-1); color: var(--text);
  font-size: var(--fs-label); font-weight: var(--fw-semi);
}
.pager__item:hover:not([aria-disabled="true"]) { border-color: var(--border-strong); background: var(--surface-3); }
.pager__item[aria-current="page"] { background: var(--accent); color: var(--accent-ink); border-color: transparent; }
.pager__item[aria-disabled="true"] { opacity: .45; pointer-events: none; }
.pager__gap { color: var(--text-subtle); padding-inline: var(--sp-1); }

/* --- Tabs --------------------------------------------------------------- */

.tabs__list {
  display: flex; gap: var(--sp-1);
  border-bottom: 1px solid var(--border);
  overflow-x: auto; scrollbar-width: none;
}
.tabs__list::-webkit-scrollbar { display: none; }
.tabs__tab {
  min-height: var(--tap-min);
  padding: 0 var(--sp-4);
  border: 0; background: none; cursor: pointer;
  border-bottom: 2px solid transparent;
  color: var(--text-muted);
  font-size: var(--fs-label); font-weight: var(--fw-bold);
  white-space: nowrap;
  transition: color var(--dur-base) var(--ease-out), border-color var(--dur-base) var(--ease-out);
}
.tabs__tab:hover { color: var(--text-strong); }
.tabs__tab[aria-selected="true"] { color: var(--accent); border-bottom-color: var(--accent); }
.tabs__panel { padding-top: var(--sp-6); }
.tabs__panel[hidden] { display: none; }

/* --- Responsive --------------------------------------------------------- */

.hdr__burger { display: none; }

@media (max-width: 1024px) {
  .hdr__nav { display: none; }
  .hdr__burger { display: inline-grid; }
  .hdr__actions .btn--hide-mobile { display: none; }
}
@media (max-width: 900px) {
  .mega__grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 600px) {
  .hdr__utility { display: none; }
  .hdr__bar { min-height: 60px; padding-inline: var(--sp-3); }
  .hdr__mark { width: 36px; height: 36px; }
}

/* --- Social links ---------------------------------------------------------
   Small round buttons. They keep the 44px touch target through padding on
   the list item rather than a huge visible circle.                        */
.social { display: flex; gap: var(--sp-1); list-style: none; margin: 0; padding: 0; align-items: center; }
.social__link {
  display: grid; place-items: center;
  width: 34px; height: 34px;
  border-radius: 50%;
  font-size: 13px; font-weight: var(--fw-bold);
  color: var(--text-muted);
  background: var(--surface-3);
  transition: background var(--dur-base) var(--ease-out), color var(--dur-base) var(--ease-out),
              transform var(--dur-base) var(--ease-out);
}
.social__link:hover { background: var(--accent); color: var(--accent-ink); transform: translateY(-2px); }
.social__link:focus-visible { outline: 3px solid var(--focus-ring); outline-offset: 2px; }

.social--footer .social__link {
  background: color-mix(in srgb, var(--text-inverse) 12%, transparent);
  color: var(--text-inverse);
}
.social--footer .social__link:hover { background: var(--accent); color: var(--accent-ink); }

@media (max-width: 900px) {
  /* In the top utility strip there is no room; the footer set still shows. */
  .social--header { display: none; }
}

/* --- Header dropdowns -----------------------------------------------------
   Opens on hover for pointers and on focus for keyboards, so it is reachable
   without a mouse. Touch users tap through to the parent page instead.    */
.hdr__has-sub { position: relative; display: inline-flex; }
.hdr__caret { font-size: 9px; margin-inline-start: 4px; opacity: .7; }
.hdr__sub {
  position: absolute; inset-block-start: 100%; inset-inline-start: 0;
  min-width: 200px;
  padding: var(--sp-2);
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  box-shadow: var(--shadow-overlay);
  display: grid; gap: 1px;
  opacity: 0; visibility: hidden; transform: translateY(6px);
  transition: opacity var(--dur-base) var(--ease-out), transform var(--dur-base) var(--ease-out),
              visibility var(--dur-base);
  z-index: var(--z-dropdown, 60);
}
.hdr__has-sub:hover .hdr__sub,
.hdr__has-sub:focus-within .hdr__sub { opacity: 1; visibility: visible; transform: none; }
.hdr__sublink {
  display: block; padding: var(--sp-2) var(--sp-3); min-height: var(--tap-min);
  display: flex; align-items: center;
  border-radius: var(--r-sm);
  font-size: var(--fs-label); font-weight: var(--fw-medium);
  color: var(--text-muted);
}
.hdr__sublink:hover { background: var(--surface-3); color: var(--text-strong); }
.hdr__sublink:focus-visible { outline: 3px solid var(--focus-ring); outline-offset: -2px; }

.drawer__link--sub {
  padding-inline-start: var(--sp-8);
  font-size: var(--fs-label);
  color: var(--text-muted);
}
.drawer__link--sub::before { content: "↳ "; opacity: .5; }