/* ════════════════════════════════════════════════════════════════
   EDUCATION — MUSEUM TIMELINE LAYER
   Scoped to `.edu-museum` (added on <body> alongside `.edu-root`).
   Reuses the existing design tokens from assets/style.css and the
   editorial atlas system in education.css — this file only adds the
   timeline spine, the cinematic stage chrome, and the entrance hub.

   Everything degrades gracefully: with no JS (or prefers-reduced-
   motion) the page renders as the existing static atlas. The GSAP
   layer in museum.js only *enhances* — it never gates content.
   ════════════════════════════════════════════════════════════════ */

.edu-museum {
  --museum-spine-w: 15rem;
  --museum-node: 13px;
  --museum-ink: var(--navy);
  --museum-rail: color-mix(in srgb, var(--olive) 22%, var(--gray-200));
  --museum-rail-fill: var(--olive);
}

/* ────────────────────────────────────────────────────────────────
   1 · THE ENTRANCE HERO (tour)
   A full-height "gallery threshold" that sets the museum tone before
   the timeline proper begins.
   ──────────────────────────────────────────────────────────────── */
.museum-hero {
  position: relative;
  min-height: 100svh;
  display: grid;
  align-content: center;
  padding: 7rem 2rem 5rem;
  overflow: hidden;
  border-bottom: 1px solid var(--museum-rail);
  background:
    radial-gradient(120% 80% at 15% 0%, color-mix(in srgb, var(--olive) 9%, transparent), transparent 60%),
    var(--warm-bg);
}

.museum-hero-inner {
  max-width: var(--edu-wide, 1080px);
  margin: 0 auto;
  width: 100%;
}

.museum-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: .6rem;
  font-size: .74rem;
  font-weight: 700;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--olive-dark);
}

.museum-eyebrow::before {
  content: "";
  width: 2.2rem;
  height: 1px;
  background: var(--olive);
}

.museum-hero h1 {
  font-size: clamp(2.6rem, 6.5vw, 5.2rem);
  line-height: 1.04;
  letter-spacing: -0.01em;
  margin: 1.4rem 0 1.2rem;
  max-width: 16ch;
}

.museum-hero-lede {
  font-size: clamp(1.05rem, 1.8vw, 1.3rem);
  color: var(--gray-600);
  max-width: 60ch;
  line-height: 1.7;
}

.museum-hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 1.2rem 2.5rem;
  margin-top: 2.5rem;
  padding-top: 1.6rem;
  border-top: 1px solid var(--museum-rail);
  max-width: 60ch;
}
.museum-hero-stat { display: grid; gap: .15rem; }
.museum-hero-stat b {
  font-family: 'Playfair Display', serif;
  font-size: 1.9rem;
  color: var(--navy);
  line-height: 1;
}
.museum-hero-stat span {
  font-size: .72rem;
  font-weight: 700;
  letter-spacing: .07em;
  text-transform: uppercase;
  color: var(--gray-500);
}

.museum-scroll-cue {
  position: absolute;
  left: 50%;
  bottom: 1.6rem;
  transform: translateX(-50%);
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: .5rem;
  font-size: .68rem;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--gray-500);
}
.museum-scroll-cue span {
  width: 1px;
  height: 2.2rem;
  background: linear-gradient(var(--olive), transparent);
}

/* orientation "wall text" panel between the hero and the first gallery */
.museum-intro {
  padding: clamp(2.5rem, 7vh, 4.5rem) 2rem clamp(1rem, 3vh, 2rem);
  border-bottom: 1px solid var(--museum-rail);
}
.museum-intro-inner {
  max-width: 62ch;
  margin: 0 auto;
}
.museum-intro p {
  font-size: clamp(1.05rem, 1.7vw, 1.28rem);
  line-height: 1.85;
  color: var(--gray-600);
  border-left: 2px solid var(--olive);
  padding-left: 1.6rem;
}

/* ────────────────────────────────────────────────────────────────
   2 · THE TIMELINE SPINE
   A fixed rail (desktop) that tracks scroll progress and highlights
   the current era. On narrow screens it collapses into the sticky
   horizontal chip strip already defined by .edu-toc in education.css,
   so this rail is simply hidden there.
   ──────────────────────────────────────────────────────────────── */
.museum-spine {
  position: fixed;
  top: 0;
  left: 0;
  height: 100vh;
  width: var(--museum-spine-w);
  z-index: 15;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 6rem 1.1rem 6rem 1.6rem;
  pointer-events: none;
  opacity: 0;
  transition: opacity .4s ease;
}
.museum-spine.is-ready { opacity: 1; }

.museum-spine-title {
  font-size: .66rem;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--gray-500);
  margin-bottom: 1.2rem;
  padding-left: 1.75rem;
}

.museum-spine-track {
  position: relative;
  display: grid;
  gap: 0;
}

/* the base rail + the animated fill sit behind the nodes */
.museum-spine-rail,
.museum-spine-fill {
  position: absolute;
  left: 5px;
  top: .55rem;
  bottom: .55rem;
  width: 2px;
  border-radius: 2px;
}
.museum-spine-rail { background: var(--museum-rail); }
.museum-spine-fill {
  background: var(--museum-rail-fill);
  transform-origin: top center;
  transform: scaleY(0);
  bottom: auto;
  height: calc(100% - 1.1rem);
}

.museum-spine-node {
  position: relative;
  display: grid;
  grid-template-columns: 12px 1fr;
  align-items: center;
  gap: .8rem;
  padding: .5rem 0;
  pointer-events: auto;
  text-decoration: none;
  color: var(--gray-500);
  transition: color .25s ease;
}
.museum-spine-dot {
  width: var(--museum-node);
  height: var(--museum-node);
  margin-left: -1px;
  border-radius: 50%;
  background: var(--warm-bg);
  border: 2px solid var(--museum-rail);
  box-shadow: 0 0 0 4px var(--warm-bg);
  transition: border-color .25s ease, background .25s ease, transform .25s ease;
}
.museum-spine-label { display: grid; gap: .1rem; }
.museum-spine-era {
  font-size: .62rem;
  font-weight: 700;
  letter-spacing: .05em;
  text-transform: uppercase;
  color: var(--gray-400);
}
.museum-spine-name {
  font-size: .82rem;
  font-weight: 600;
  line-height: 1.2;
}

.museum-spine-node.is-complete .museum-spine-dot {
  background: var(--olive);
  border-color: var(--olive);
}
.museum-spine-node.is-current {
  color: var(--navy);
}
.museum-spine-node.is-current .museum-spine-dot {
  background: var(--olive);
  border-color: var(--olive);
  transform: scale(1.35);
}
.museum-spine-node.is-current .museum-spine-era { color: var(--olive-dark); }
.museum-spine-node:hover { color: var(--navy); }
.museum-spine-node:focus-visible { outline: 2px solid var(--olive); outline-offset: 4px; border-radius: 6px; }

/* push the tour content right so the fixed spine doesn't overlap it */
@media (min-width: 1180px) {
  .edu-museum main { padding-left: var(--museum-spine-w); }
  .edu-museum .museum-hero { padding-left: calc(var(--museum-spine-w) + 2rem); }
  /* the old right-side floating TOC is redundant once the spine exists */
  .edu-museum .edu-toc { display: none; }
}
@media (max-width: 1179px) {
  .museum-spine { display: none; }
}

/* ────────────────────────────────────────────────────────────────
   3 · CINEMATIC STAGE CHROME
   Layered on top of the existing .edu-atlas-stage grid. Adds the era
   dateline, an artifact frame with parallax + a caption plate, and
   the reveal states the JS toggles.
   ──────────────────────────────────────────────────────────────── */
.edu-museum .edu-atlas-stage {
  position: relative;
  min-height: 92vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  scroll-margin-top: 0;
}

/* a large translucent era numeral behind each stage — museum wall label */
.museum-stage-index {
  position: absolute;
  top: clamp(1rem, 4vw, 3rem);
  right: clamp(1rem, 5vw, 4rem);
  font-family: 'Playfair Display', serif;
  font-weight: 700;
  font-size: clamp(5rem, 16vw, 13rem);
  line-height: .8;
  color: color-mix(in srgb, var(--olive) 12%, transparent);
  pointer-events: none;
  z-index: 0;
  user-select: none;
}

.edu-museum .edu-atlas-stage-inner { position: relative; z-index: 1; }

.museum-dateline {
  display: inline-flex;
  align-items: baseline;
  gap: .6rem;
  font-family: 'Playfair Display', serif;
  color: var(--olive-dark);
  margin-bottom: .5rem;
}
.museum-dateline b { font-size: 1.25rem; font-weight: 700; }
.museum-dateline span {
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: .7rem;
  font-weight: 700;
  letter-spacing: .09em;
  text-transform: uppercase;
  color: var(--gray-500);
}

/* artifact frame — the "in a museum case" treatment for each figure */
.edu-museum .edu-atlas-visual {
  position: relative;
  padding: 1.1rem;
  background: linear-gradient(160deg, var(--white), color-mix(in srgb, var(--warm-bg) 60%, var(--white)));
  border: 1px solid var(--museum-rail);
  border-radius: 4px;
  box-shadow: var(--shadow-lg);
}
.edu-museum .edu-atlas-visual::after {
  content: "";
  position: absolute;
  inset: .45rem;
  border: 1px solid color-mix(in srgb, var(--olive) 18%, transparent);
  border-radius: 2px;
  pointer-events: none;
}
.edu-museum .edu-atlas-visual img {
  border-radius: 2px;
  will-change: transform;
}
.museum-plate {
  margin-top: .9rem;
  padding-top: .75rem;
  border-top: 1px solid var(--museum-rail);
  font-size: .74rem;
  line-height: 1.5;
  color: var(--gray-500);
}
.museum-plate b { color: var(--gray-700); font-weight: 700; display: block; margin-bottom: .15rem; }

/* reveal states (JS-driven; static fallback shows everything) */
.edu-museum.js-on .museum-anim { opacity: 0; }

/* ────────────────────────────────────────────────────────────────
   4 · ERA INTERSTITIALS
   Full-width chronological dividers between grouped eras, like
   walking into a new wing of the museum.
   ──────────────────────────────────────────────────────────────── */
.museum-wing {
  position: relative;
  padding: clamp(4rem, 12vh, 9rem) 2rem;
  text-align: center;
  border-top: 1px solid var(--museum-rail);
  background:
    linear-gradient(180deg, color-mix(in srgb, var(--olive) 5%, transparent), transparent);
}
.museum-wing-era {
  font-size: .74rem;
  font-weight: 700;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--olive-dark);
}
.museum-wing h2 {
  font-size: clamp(1.8rem, 4vw, 3rem);
  margin: .8rem auto .6rem;
  max-width: 20ch;
}
.museum-wing p {
  max-width: 54ch;
  margin: 0 auto;
  color: var(--gray-600);
  font-size: 1.02rem;
}

/* ────────────────────────────────────────────────────────────────
   5 · THE MUSEUM ENTRANCE HUB (education/index.html)
   Reframes the hub as one chronological floor plan: the tour is the
   main spine, deep-dives are annexes, reference is the archive.
   ──────────────────────────────────────────────────────────────── */
.museum-hub-hero {
  position: relative;
  padding: clamp(5rem, 14vh, 9rem) 2rem clamp(3rem, 7vh, 5rem);
  overflow: hidden;
  background:
    radial-gradient(90% 70% at 80% 0%, color-mix(in srgb, var(--olive) 8%, transparent), transparent 55%),
    var(--warm-bg);
  border-bottom: 1px solid var(--museum-rail);
}
.museum-hub-hero-inner { max-width: var(--edu-wide, 1080px); margin: 0 auto; }
.museum-hub-hero h1 {
  font-size: clamp(2.5rem, 6vw, 4.6rem);
  line-height: 1.05;
  margin: 1.3rem 0 1.1rem;
  max-width: 18ch;
}
.museum-hub-hero p {
  font-size: clamp(1.02rem, 1.6vw, 1.22rem);
  color: var(--gray-600);
  max-width: 60ch;
  line-height: 1.7;
}
.museum-hub-cta {
  display: inline-flex;
  align-items: center;
  gap: .6rem;
  margin-top: 2rem;
  padding: .85rem 1.5rem;
  background: var(--olive);
  color: #fff;
  font-weight: 700;
  font-size: .92rem;
  text-decoration: none;
  border-radius: 999px;
  transition: background .18s ease, transform .18s ease;
}
.museum-hub-cta:hover { background: var(--olive-dark); transform: translateY(-2px); }

/* the horizontal floor-plan timeline strip on the hub */
.museum-floorplan {
  padding: clamp(3.5rem, 9vh, 6rem) 0;
  overflow: hidden;
}
.museum-floorplan-head {
  max-width: var(--edu-wide, 1080px);
  margin: 0 auto 2.5rem;
  padding: 0 2rem;
}
.museum-floorplan-head .edu-section-label { margin-bottom: .6rem; }
.museum-floorplan-head h2 { font-size: clamp(1.6rem, 3.4vw, 2.4rem); max-width: 24ch; }

.museum-rail-scroll {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: minmax(248px, 288px);
  gap: 1.25rem;
  overflow-x: auto;
  scroll-snap-type: x proximity;
  padding: 1.5rem 2rem 2rem;
  scrollbar-width: thin;
}
.museum-rail-scroll::-webkit-scrollbar { height: 8px; }
.museum-rail-scroll::-webkit-scrollbar-thumb { background: var(--museum-rail); border-radius: 999px; }

.museum-stop {
  position: relative;
  scroll-snap-align: start;
  display: flex;
  flex-direction: column;
  padding: 1.4rem 1.4rem 1.5rem;
  background: var(--white);
  border: 1px solid var(--museum-rail);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  text-decoration: none;
  color: inherit;
  transition: transform .18s ease, box-shadow .18s ease, border-color .18s ease;
}
.museum-stop::before {
  content: "";
  position: absolute;
  top: -1.5rem;
  left: 1.6rem;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--olive);
  box-shadow: 0 0 0 4px var(--warm-bg);
}
.museum-stop::after {
  content: "";
  position: absolute;
  top: -1.05rem;
  left: 2.1rem;
  right: -1.25rem;
  height: 2px;
  background: var(--museum-rail);
}
.museum-stop:last-child::after { display: none; }
.museum-stop:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: var(--olive-light); }
.museum-stop-era {
  font-family: 'Playfair Display', serif;
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--olive-dark);
  margin-bottom: .5rem;
}
.museum-stop-kind {
  font-size: .66rem;
  font-weight: 700;
  letter-spacing: .07em;
  text-transform: uppercase;
  color: var(--gray-400);
  margin-bottom: .55rem;
}
.museum-stop h3 { font-size: 1.18rem; margin-bottom: .5rem; line-height: 1.25; }
.museum-stop p { font-size: .88rem; color: var(--gray-600); margin: 0; line-height: 1.55; }

/* annex grid (deep dives + reference) keeps the existing card system,
   just re-labelled as museum annexes via the section header */
.museum-annex { padding: clamp(3rem, 7vh, 5rem) 0; border-top: 1px solid var(--museum-rail); }
.museum-annex .edu-container { max-width: var(--edu-wide, 1080px); }

/* ────────────────────────────────────────────────────────────────
   5b · THE INSTRUMENT ROOM (education/gallery/)
   A wing of full-size, hands-on interactives. Each exhibit frames one
   .edu-model mount with a numbered plinth label, context, and a link
   back to the chapter it belongs to.
   ──────────────────────────────────────────────────────────────── */
.museum-exhibit {
  padding: clamp(3rem, 8vh, 6rem) 2rem;
  border-top: 1px solid var(--museum-rail);
}
.museum-exhibit:first-of-type { border-top: 0; }
.museum-exhibit-inner {
  max-width: 920px;
  margin: 0 auto;
}
.museum-exhibit-plinth {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  margin-bottom: 1rem;
}
.museum-exhibit-num {
  font-family: 'Playfair Display', serif;
  font-weight: 700;
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  color: color-mix(in srgb, var(--olive) 55%, var(--gray-400));
  line-height: 1;
}
.museum-exhibit-kind {
  font-size: .68rem;
  font-weight: 700;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--olive-dark);
}
.museum-exhibit h2 {
  font-size: clamp(1.7rem, 3.4vw, 2.5rem);
  margin: 0 0 .7rem;
}
.museum-exhibit-lede {
  font-size: 1.08rem;
  line-height: 1.7;
  color: var(--gray-600);
  max-width: 62ch;
  margin-bottom: .4rem;
}
.museum-exhibit-back {
  display: inline-flex;
  gap: .4rem;
  margin: .6rem 0 1.5rem;
  font-size: .82rem;
  font-weight: 700;
  color: var(--navy);
  text-decoration: none;
  border-bottom: 1px solid var(--olive);
  padding-bottom: .15rem;
}
.museum-exhibit-back:hover { color: var(--olive-dark); }

/* ────────────────────────────────────────────────────────────────
   5d · THE CLOSING BRIDGE (end of the tour timeline)
   The museum's one deliberate turn toward the product — a calm
   epilogue "wall," not a pitch. Reading-width, editorial.
   ──────────────────────────────────────────────────────────────── */
.museum-bridge {
  padding: clamp(4rem, 10vh, 7rem) 2rem;
  border-top: 1px solid var(--museum-rail);
  background:
    radial-gradient(120% 90% at 50% 0%, color-mix(in srgb, var(--olive) 7%, transparent), transparent 62%),
    var(--warm-bg);
}
.museum-bridge-inner {
  max-width: var(--edu-reading, 68ch);
  margin: 0 auto;
}
.museum-bridge h2 {
  font-size: clamp(2rem, 4.5vw, 3rem);
  line-height: 1.08;
  margin: 1rem 0;
}
.museum-bridge-dek {
  font-family: 'Playfair Display', serif;
  font-style: italic;
  font-size: clamp(1.15rem, 2vw, 1.5rem);
  line-height: 1.5;
  color: var(--gray-700);
  margin-bottom: 2rem;
}
.museum-bridge-body p {
  font-size: 18px;
  line-height: 1.82;
  color: var(--gray-700);
  margin-bottom: 1.3rem;
}
.museum-bridge-close {
  font-family: 'Playfair Display', serif;
  font-size: clamp(1.15rem, 2vw, 1.35rem);
  color: var(--navy);
  border-top: 1px solid var(--museum-rail);
  padding-top: 1.5rem;
  margin-top: .5rem;
}
@media (min-width: 1180px) {
  /* the fixed spine already pads main; keep the epilogue centered in the remaining space */
  .edu-museum .museum-bridge { padding-left: 2rem; padding-right: 2rem; }
}
@media (prefers-color-scheme: dark) {
  .edu-museum .museum-bridge { background: var(--d-bg, #0d130a); }
  .edu-museum .museum-bridge-dek,
  .edu-museum .museum-bridge-body p { color: var(--d-dim, rgba(255,255,255,.72)); }
  .edu-museum .museum-bridge-close { color: #fff; }
}
:root[data-theme="dark"] .edu-museum .museum-bridge { background: var(--d-bg, #0d130a); }
:root[data-theme="dark"] .edu-museum .museum-bridge-dek,
:root[data-theme="dark"] .edu-museum .museum-bridge-body p { color: var(--d-dim, rgba(255,255,255,.72)); }
:root[data-theme="dark"] .edu-museum .museum-bridge-close { color: #fff; }

/* ────────────────────────────────────────────────────────────────
   6 · DARK MODE
   ──────────────────────────────────────────────────────────────── */
@media (prefers-color-scheme: dark) {
  .edu-museum {
    --museum-rail: color-mix(in srgb, var(--olive-light) 22%, transparent);
  }
  .edu-museum .museum-hero,
  .edu-museum .museum-hub-hero {
    background:
      radial-gradient(110% 80% at 15% 0%, color-mix(in srgb, var(--olive-light) 8%, transparent), transparent 60%),
      var(--d-bg, #0d130a);
  }
  .edu-museum .museum-spine-dot { background: var(--d-bg, #0d130a); box-shadow: 0 0 0 4px var(--d-bg, #0d130a); }
  .edu-museum .edu-atlas-visual { background: var(--d-card, rgba(255,255,255,.035)); }
  .edu-museum .museum-stop { background: var(--d-card, rgba(255,255,255,.035)); }
  .edu-museum .museum-stop::before,
  .edu-museum .museum-stop::after { box-shadow: 0 0 0 4px var(--d-bg, #0d130a); }
  .edu-museum .museum-plate b { color: rgba(255,255,255,.8); }
}
:root[data-theme="dark"] .edu-museum {
  --museum-rail: color-mix(in srgb, var(--olive-light) 22%, transparent);
}
:root[data-theme="dark"] .edu-museum .museum-hero,
:root[data-theme="dark"] .edu-museum .museum-hub-hero {
  background:
    radial-gradient(110% 80% at 15% 0%, color-mix(in srgb, var(--olive-light) 8%, transparent), transparent 60%),
    var(--d-bg, #0d130a);
}
:root[data-theme="dark"] .edu-museum .museum-spine-dot { background: var(--d-bg, #0d130a); box-shadow: 0 0 0 4px var(--d-bg, #0d130a); }
:root[data-theme="dark"] .edu-museum .edu-atlas-visual { background: var(--d-card, rgba(255,255,255,.035)); }
:root[data-theme="dark"] .edu-museum .museum-stop { background: var(--d-card, rgba(255,255,255,.035)); }
:root[data-theme="dark"] .edu-museum .museum-stop::before,
:root[data-theme="dark"] .edu-museum .museum-stop::after { box-shadow: 0 0 0 4px var(--d-bg, #0d130a); }

/* ────────────────────────────────────────────────────────────────
   7 · REDUCED MOTION & SMALL SCREENS
   ──────────────────────────────────────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
  .edu-museum.js-on .museum-anim { opacity: 1 !important; transform: none !important; }
  .museum-scroll-cue { display: none; }
}

@media (max-width: 1179px) {
  .edu-museum main { padding-left: 0; }
  .edu-museum .museum-hero { padding-left: 2rem; }
}
@media (max-width: 640px) {
  .museum-hero { min-height: auto; padding: 5rem 1.5rem 3.5rem; }
  .edu-museum .edu-atlas-stage { min-height: auto; }
  .museum-stage-index { font-size: 4.5rem; opacity: .7; }
  .museum-rail-scroll { grid-auto-columns: minmax(220px, 82vw); padding: 1.5rem 1.25rem 2rem; }
}
