// ─────────────────────────────────────────────────────────────
// protected/bifrost.js — Project Bifrost scenes inside the
// Overview page of the timeline.
//
// This file:
//   1. Wraps the Overview's scroll-bound scenes (hero → aurora arc
//      → treasure-map). The 4-card architecture stack, the "This is
//      why we've invited you" word fly-in, and the Project Bifrost
//      Join CTA were removed in the 2026-05-19 customer-presentation
//      conversion; the architecture explainer (formerly /deepdive)
//      now follows the treasure-map inline — see protected/platform.js.
//   2. Rewires Lenis smooth scroll + GSAP ScrollTrigger so the
//      scroller is the Overview's internal scrolling container —
//      never the window — so the three-page Timeline/Overview/
//      Timeline model (each fixed-viewport) keeps working.
//   3. Drives the Europe map's opacity from the scroller's scroll
//      position: fully visible at the top, fades to 0 as the user
//      scrolls into the hero, fades back in on scrolling up.
//   4. Is a lazy-init module. Nothing happens at page load; the
//      dot-nav handler in timeline.js calls window.__bifrost.init()
//      the first time the Overview page becomes active.
//
// CSP: 'script-src self'. No inline scripts anywhere.
// ─────────────────────────────────────────────────────────────

(function () {
  'use strict';

  // Lazy single-shot init flag — nav can click the Overview pip
  // multiple times; we only wire everything up once.
  let initialized = false;
  let refreshScheduled = false;

  // Shared state between init() and the public surface (scrollTo etc).
  // These are assigned once during init(); scrollTo reads them to drive
  // the Overview's internal scroller instead of window scroll.
  let lenisInstance = null;
  let scrollerEl = null;

  // A tiny helper: schedule a ScrollTrigger.refresh() on the next
  // animation frame, de-duplicating calls within the same frame.
  function scheduleRefresh() {
    if (refreshScheduled || !window.ScrollTrigger) return;
    refreshScheduled = true;
    requestAnimationFrame(() => {
      refreshScheduled = false;
      window.ScrollTrigger.refresh();
    });
  }

  function init() {
    if (initialized) {
      // Already booted — just re-measure, in case layout shifted while
      // the page was inactive (e.g. user resized the window on Timeline).
      scheduleRefresh();
      return;
    }
    initialized = true;

    // Guard: vendor libs must have loaded.
    if (typeof window.gsap === 'undefined' ||
        typeof window.ScrollTrigger === 'undefined' ||
        typeof window.Lenis === 'undefined') {
      console.warn('[bifrost] Vendor libraries (gsap/ScrollTrigger/Lenis) missing; skipping init.');
      return;
    }

    const reduceMotion = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

    // Reveal-on-load elements: if reduced motion, just make them visible
    // and bail before registering any ScrollTrigger-bound tweens.
    if (reduceMotion) {
      document.querySelectorAll('#page-overview [data-reveal], #page-overview [data-reveal-lines]').forEach(el => {
        el.style.opacity = '1';
        el.style.transform = 'none';
      });
      // The hero-wrap is hidden by CSS (`.js .hero-wrap { opacity: 0 }`)
      // to prevent a flash during page activation — unhide it here since
      // we're skipping the fade-in tween.
      const heroWrap = document.querySelector('.hero-wrap');
      if (heroWrap) heroWrap.style.opacity = '1';
      // Still fade the Europe map fully in — it's the scene background.
      const mapEl = document.getElementById('overview-globe');
      if (mapEl) mapEl.style.opacity = '1';
      return;
    }

    // ─── Scroller setup ──────────────────────────────────────────
    //
    // The Overview is a fixed-position .page that contains one
    // scrollable child: `#overview-scroll`. All six scenes live
    // inside it. Lenis drives wheel input on that element;
    // ScrollTrigger reads scroll from the same element.
    const scroller = document.getElementById('overview-scroll');
    if (!scroller) {
      console.error('[bifrost] #overview-scroll not found');
      return;
    }
    scrollerEl = scroller;

    const gsap = window.gsap;
    const ScrollTrigger = window.ScrollTrigger;
    const Lenis = window.Lenis;

    gsap.registerPlugin(ScrollTrigger);

    // Lenis wired to the Overview's internal scroller, NOT the window.
    const lenis = new Lenis({
      wrapper: scroller,
      content: scroller.firstElementChild,
      duration: 1.15,
      easing: (t) => Math.min(1, 1.001 - Math.pow(2, -10 * t)),
      smoothWheel: true,
      wheelMultiplier: 1,
      touchMultiplier: 1.5,
    });

    // Tell ScrollTrigger how to read/write scroll on this scroller.
    ScrollTrigger.scrollerProxy(scroller, {
      scrollTop(value) {
        if (arguments.length) {
          scroller.scrollTop = value;
        }
        return scroller.scrollTop;
      },
      getBoundingClientRect() {
        // The scroller occupies the full viewport (inset: 0 on its parent).
        return { top: 0, left: 0, width: window.innerWidth, height: window.innerHeight };
      },
      // Scrollbars are hidden via CSS; pinType is 'transform' for nested scrollers.
      pinType: 'transform',
    });

    // Every ScrollTrigger below implicitly targets our scroller.
    ScrollTrigger.defaults({ scroller });

    // Pump Lenis via GSAP's ticker; notify ScrollTrigger on each scroll.
    lenis.on('scroll', ScrollTrigger.update);
    gsap.ticker.add((time) => lenis.raf(time * 1000));
    gsap.ticker.lagSmoothing(0);

    // Expose lenis to scrollTo() via the shared closure var.
    lenisInstance = lenis;

    // ─── Europe map fade ─────────────────────────────────────────
    //
    // Fully visible at scrollTop=0. Fades to 0 between 20% and 80%
    // of viewport height. Fades back in on scrolling up. Opacity
    // ceiling is 0.42 — matches the original .page-overview.is-active
    // .overview-globe svg look.
    const mapSvg = document.querySelector('#overview-globe svg');
    const MAP_MAX_OPACITY = 0.42;
    if (mapSvg) {
      // Initial: visible (map is the hero backdrop). We'll drive opacity
      // directly on every scroll tick, so kill any CSS opacity transition
      // (the existing rule animates opacity over 900ms — would be janky).
      mapSvg.style.transition = 'none';
      mapSvg.style.opacity = MAP_MAX_OPACITY.toFixed(3);
    }

    function updateMapOpacity() {
      if (!mapSvg) return;
      const vh = window.innerHeight;
      const y = scroller.scrollTop;
      // Between 0.20 × vh and 0.80 × vh, ramp from full to zero.
      const startFade = vh * 0.20;
      const endFade   = vh * 0.80;
      let t;
      if (y <= startFade) {
        t = 0; // fully visible
      } else if (y >= endFade) {
        t = 1; // fully hidden
      } else {
        t = (y - startFade) / (endFade - startFade);
      }
      mapSvg.style.opacity = (MAP_MAX_OPACITY * (1 - t)).toFixed(3);
    }

    lenis.on('scroll', updateMapOpacity);
    // Initial paint
    updateMapOpacity();

    // ─── Scroll-spy for the dot-nav ──────────────────────────────
    //
    // As the user scrolls through the Overview, update the active dot
    // to match the scene currently in view. Called from lenis.on('scroll')
    // at display rate; debounced implicitly by requestAnimationFrame
    // through the shared refresh scheduler.
    //
    // Logic: a scene is "active" when its top is above the viewport's
    // midpoint AND its bottom is below it. For stacked pinned scenes
    // (S2) the pin duration makes "bottom" go well past the viewport,
    // so the first-match wins — scenes are checked top-to-bottom.
    // Every scrollable scene in the Overview, top-to-bottom. The
    // scroll-spy walks this list and decides which one is "in
    // view" by the viewport midline rule below. Intermediate
    // scenes (bifrost-meaning, platform-question) map to a
    // neighbouring dot via sceneToDot so the nav stays highlighted
    // through them.
    const sceneOrder = [
      'hero',
      'bifrost', 'bifrost-meaning',
      'platform-question', 'platform-layers',
      'wiki-deepdive',
      'platform-cards',
      'platform-roadmap',
    ];
    // Maps a scene's id to the data-scroll-to of the dot that
    // should highlight when that scene is in view.
    //   bifrost-meaning   → bifrost           (treasure-map is a
    //                                          continuation of the
    //                                          Project Bifrost reveal)
    //   platform-question → platform-layers   (framing lead-in to
    //                                          the architecture)
    const sceneToDot = {
      'hero':              'hero',
      'bifrost':           'bifrost',
      'bifrost-meaning':   'bifrost',
      'platform-question': 'platform-layers',
      'platform-layers':   'platform-layers',
      'wiki-deepdive':     'wiki-deepdive',
      'platform-cards':    'platform-cards',
      'platform-roadmap':  'platform-roadmap',
    };
    let lastActiveScene = null;
    function updateActiveSceneDot() {
      if (typeof window.__setActiveDot !== 'function') return;
      const midY = window.innerHeight * 0.5;
      let visibleId = sceneOrder[0];
      for (const id of sceneOrder) {
        const el = document.getElementById(id);
        if (!el) continue;
        const r = el.getBoundingClientRect();
        // A scene whose top is at or above the midline, but whose
        // bottom hasn't scrolled past the midline yet.
        if (r.top <= midY && r.bottom > midY) {
          visibleId = id;
          break;
        }
        // Edge case: scrolled past — keep latest seen as fallback.
        if (r.top <= midY) visibleId = id;
      }
      if (visibleId !== lastActiveScene) {
        lastActiveScene = visibleId;
        window.__setActiveDot('page-overview', sceneToDot[visibleId] || visibleId);
      }
    }
    lenis.on('scroll', updateActiveSceneDot);
    // Initial paint: set "hero" active since we start at top.
    requestAnimationFrame(updateActiveSceneDot);

    // ─── Topography parallax ─────────────────────────────────────
    //
    // Concentric-ring topographic layer that sits behind the Europe
    // map (z-index 0). Generated at runtime — same formula as the
    // entrance page's .currents pattern but rotated/offset so it reads
    // as a visual sibling rather than a duplicate.
    //
    // Parallax speed: 0.15× of the scroller's scrollTop. Slow enough to
    // feel atmospheric, fast enough that the layer doesn't appear
    // static on casual scroll. Applied as a translateY composed WITH
    // the 40° rotate from CSS (so we build the full transform here to
    // avoid clobbering the CSS rotate).
    const topoWrap = document.getElementById('overview-topography');
    if (topoWrap && !topoWrap.querySelector('svg')) {
      const svgNS = 'http://www.w3.org/2000/svg';
      const svg = document.createElementNS(svgNS, 'svg');
      const W = 1600, H = 1600, cx = W * 0.5, cy = H * 0.5;
      svg.setAttribute('viewBox', `0 0 ${W} ${H}`);
      svg.setAttribute('preserveAspectRatio', 'xMidYMid meet');

      // Slightly different parameters from the entrance page's currents
      // so the rings read as "related but not identical":
      //   - more rings (34 vs 26) — denser
      //   - smaller step (28 vs 32) — tighter
      //   - larger amplitude (32 vs 26) — wavier
      //   - lower base opacity — quieter behind the map
      const RINGS = 34, BASE_R = 60, STEP = 28, AMP = 32;
      for (let i = 0; i < RINGS; i++) {
        const r = BASE_R + i * STEP, segs = 280;
        const p1 = (i * 0.7) % (Math.PI * 2);
        const p2 = (i * 1.4 + 1.3) % (Math.PI * 2);
        const a1 = AMP * (0.9 + (i % 5) * 0.08);
        const a2 = AMP * 0.35;
        let d = '';
        for (let s = 0; s <= segs; s++) {
          const t = (s / segs) * Math.PI * 2;
          const rr = r + a1 * Math.sin(t * 3 + p1 + i * 0.15)
                       + a2 * Math.sin(t * 5 + p2 + i * 0.22)
                       + AMP * 0.18 * Math.sin(t * 7 + i);
          const x = cx + Math.cos(t) * rr;
          const y = cy + Math.sin(t) * rr * 0.92;
          d += (s === 0 ? 'M' : 'L') + x.toFixed(1) + ' ' + y.toFixed(1);
        }
        d += ' Z';
        const path = document.createElementNS(svgNS, 'path');
        path.setAttribute('d', d);
        path.setAttribute('fill', 'none');
        path.setAttribute('stroke', '#383831');
        path.setAttribute('stroke-width', '1');
        path.setAttribute('stroke-linejoin', 'round');
        // Lower opacity than entrance page — sits behind the map,
        // shouldn't compete for attention.
        path.setAttribute('opacity', (i % 3 === 0 ? 0.07 : 0.04).toString());
        svg.appendChild(path);
      }
      topoWrap.appendChild(svg);
    }

    const PARALLAX_SPEED = 0.15;
    const topoSvg = topoWrap ? topoWrap.querySelector('svg') : null;
    function updateTopographyParallax() {
      if (!topoSvg) return;
      const y = scroller.scrollTop * -PARALLAX_SPEED;
      // Rotate comes from CSS (40deg); we compose our translateY into
      // the same transform string so both apply. `rotate` first so the
      // translate happens in screen space, not the rotated local space.
      topoSvg.style.transform = `translateY(${y.toFixed(1)}px) rotate(40deg)`;
    }
    lenis.on('scroll', updateTopographyParallax);
    // Initial paint
    updateTopographyParallax();

    // ─── Sticky-scroll (wheel-multiplier attenuation) ────────────
    //
    // Previous implementation multiplied Lenis's `.velocity` per scroll
    // event — ineffective, because Lenis overwrites velocity from the
    // next wheel event before that damped value is consumed.
    //
    // New approach: directly reduce Lenis's `wheelMultiplier` when the
    // viewport center is near a sticky target. The user's wheel input
    // is attenuated at the source — their next scroll produces less
    // delta, so the scene noticeably holds. When the zone is exited,
    // the multiplier is restored.
    //
    // Targets are:
    //   - Non-pinned scenes (hero, bifrost)
    //   - The treasure map (bifrost-meaning) AND each of its three
    //     stops individually — previously the whole 300vh section was
    //     one target, so users flew through the individual stops.
    //
    // platform-layers is GSAP-pinned and scrubbed; damping on top would
    // make its beat-by-beat build feel like a drag, so we exclude it.
    const BASE_WHEEL_MULT   = 1.0;
    const BASE_TOUCH_MULT   = 1.5;
    const STICKY_WHEEL_MULT = 0.35;   // 65% reduction while in a sticky zone
    const STICKY_TOUCH_MULT = 0.55;
    const STICKY_ZONE_VH    = 0.18;   // ±18% of viewport height from its center

    // Collect sticky targets. IDs of scenes + DOM refs for the three
    // individual treasure-map stops. Cached once — the list doesn't
    // change after init.
    function collectStickyTargets() {
      const targets = [];
      // platform-cards is NOT a sticky-damping target — it has its
      // own GSAP pin (see initCards in platform.js) which provides
      // the "stop" feel. Layering both would slow wheel input to
      // 0.35× during the pin and turn the 100vh budget into a
      // ~285vh slog. platform-roadmap, same.
      const sceneIds = ['hero', 'bifrost'];
      sceneIds.forEach(id => {
        const el = document.getElementById(id);
        if (el) targets.push(el);
      });
      // Treasure map intro + three stops each get their own sticky zone.
      const mapSection = document.getElementById('bifrost-meaning');
      if (mapSection) {
        // Each .map-stop is a separate card along the path — sticky them
        // individually so the user dwells on each one.
        mapSection.querySelectorAll('.map-stop').forEach(el => targets.push(el));
      }
      return targets;
    }
    const stickyTargets = collectStickyTargets();

    let wheelMultState = BASE_WHEEL_MULT;
    function updateStickyDamping() {
      const midY = window.innerHeight * 0.5;
      const zone = window.innerHeight * STICKY_ZONE_VH;
      let inZone = false;
      for (const el of stickyTargets) {
        const r = el.getBoundingClientRect();
        const elMid = (r.top + r.bottom) * 0.5;
        if (Math.abs(elMid - midY) < zone) {
          inZone = true;
          break;
        }
      }
      const nextMult = inZone ? STICKY_WHEEL_MULT : BASE_WHEEL_MULT;
      if (nextMult !== wheelMultState) {
        wheelMultState = nextMult;
        // Lenis reads options.wheelMultiplier on every wheel event —
        // re-assigning takes effect immediately.
        lenis.options.wheelMultiplier = nextMult;
        lenis.options.touchMultiplier = inZone ? STICKY_TOUCH_MULT : BASE_TOUCH_MULT;
      }
    }
    lenis.on('scroll', updateStickyDamping);
    // Initial paint (we likely start at hero which is itself a target).
    requestAnimationFrame(updateStickyDamping);

    // ─── Site-2 scene animations ─────────────────────────────────
    // (transplanted verbatim; all ScrollTriggers below automatically
    // use the Overview scroller via ScrollTrigger.defaults above.)

    // Script 1 body — HERO + SCENE 2 (architecture stack) + SCENE 3 (words) + SCENE 4 (bifrost arc)
/* -------------------------------------------------------------
     HERO — single overall fade-in. The wrap is hidden via CSS
     (`.js .hero-wrap { opacity: 0 }`) so the hero stays invisible
     during the page-activation transition, then fades in once
     Bifrost has booted.
     ------------------------------------------------------------- */
  gsap.to('.hero-wrap', {
    opacity: 1,
    duration: 1.0,
    ease: 'power2.out',
    delay: 0.1,
  });

  /* -------------------------------------------------------------
     ARCHITECTURE STACK + "This is why we've invited you" words —
     REMOVED 2026-05-19 in the customer-presentation conversion.
     The full HTML + JS is archived at
       protected/_archive/stack-scene.html
     so the 4-capabilities pinned-scrub sequence can be restored.
     ------------------------------------------------------------- */
  /* Removed: stack-scene timeline (computeGridPlan + 4-card scrubbed
     build + grid morph + copy-stage crossfade). Archived in
     protected/_archive/stack-scene.html. */

  /* Removed: words-scene "This is why we've invited you" timeline.
     Archived in protected/_archive/stack-scene.html. */

  /* -------------------------------------------------------------
     SCENE 4 — PROJECT BIFROST REVEAL
     Arc draws in, then the words settle.
     ------------------------------------------------------------- */
  const arcMain = document.getElementById('arcMain');
  const arcThin = document.getElementById('arcThin');
  const arcHalo = document.getElementById('arcHalo');
  [arcMain, arcThin, arcHalo].forEach(el => {
    if (!el) return;
    const len = el.getTotalLength();
    el.style.strokeDasharray = len;
    el.style.strokeDashoffset = len;
  });

  const tokens = gsap.utils.toArray('.bifrost-name .token');
  tokens.forEach((t, i) => {
    gsap.set(t, { opacity: 0, y: 40, filter: 'blur(10px)' });
  });

  const bifrostTl = gsap.timeline({
    scrollTrigger: {
      trigger: '#bifrost',
      start: 'top top',
      end: 'bottom bottom',
      scrub: 0.6,
    }
  });

  bifrostTl
    .to('.arc-wrap', { opacity: 1, duration: 0.1, ease: 'power2.out' }, 0.02)
    .to(arcHalo, { strokeDashoffset: 0, duration: 0.45, ease: 'power2.inOut' }, 0.02)
    .to(arcMain, { strokeDashoffset: 0, duration: 0.5, ease: 'power2.inOut' }, 0.05)
    .to(arcThin, { strokeDashoffset: 0, duration: 0.45, ease: 'power2.inOut' }, 0.12)
    .to('.bifrost-eyebrow', { opacity: 1, y: 0, duration: 0.1, ease: 'power2.out' }, 0.30)
    .fromTo('.bifrost-eyebrow', { y: 20 }, { y: 0, duration: 0.1 }, 0.30)
    .to(tokens[0], { opacity: 1, y: 0, filter: 'blur(0px)', duration: 0.15, ease: 'power3.out' }, 0.40)
    .to(tokens[1], { opacity: 1, y: 0, filter: 'blur(0px)', duration: 0.2, ease: 'power3.out' }, 0.50)
    .to('.bifrost-sub', { opacity: 1, y: 0, duration: 0.15, ease: 'power2.out' }, 0.68)
    .fromTo('.bifrost-sub', { y: 20 }, { y: 0, duration: 0.15 }, 0.68);

  // Slight parallax on the arc while the user continues to scroll
  bifrostTl.to('.arc-wrap', { y: -40, duration: 0.3, ease: 'none' }, 0.5);

  /* -------------------------------------------------------------
     On load — kick hero animation
     ------------------------------------------------------------- */
  // Ensure ScrollTrigger measures correctly after fonts load.
  if (document.fonts && document.fonts.ready) {
    document.fonts.ready.then(() => ScrollTrigger.refresh());
  }

    // Script 2 body — SCENE 5 (treasure-map) + SCENE 6 (join CTA + footer)
/* =================================================================
   PROJECT BIFROST — "What it means" treasure-map + summary cards.

   Self-contained additive IIFE. Reads the global `gsap` and
   `ScrollTrigger` registered by the existing scripts above; does
   not touch any pre-existing timelines or DOM nodes.
   ================================================================= */
/* -------------------------------------------------------------
     SCENE 5 — Treasure-map path draw + per-stop reveals
     ------------------------------------------------------------- */

  // -------- Build the path geometry from actual dot positions --------
  //
  // The treasure-map path needs to thread cleanly through each dot.
  // The dots are positioned by CSS grid/flex, so their Y positions in
  // the canvas depend on the rendered height of each stop's content
  // (which varies with viewport width and font metrics). We compute
  // the path here AFTER layout, so it always passes through the dots.
  //
  // Coordinate system: the SVG viewBox is "0 0 100 200" with
  // preserveAspectRatio="none", so X is normalised to canvas width
  // and Y to canvas height. We measure each dot's centre in canvas
  // coordinates, normalise, and emit a chain of cubic bezier segments
  // — each one bowing out to alternating sides for a meandering feel.
  const mapCanvasEl = document.querySelector('.map-canvas');
  const pathBg   = document.getElementById('mapPathBg');
  const pathDraw = document.getElementById('mapPathDraw');
  let drawScrollTrigger = null;

  function buildMapPath() {
    if (!mapCanvasEl || !pathDraw || !pathBg) return;
    const dots = mapCanvasEl.querySelectorAll('.dot-anchor');
    if (dots.length < 2) return;
    const cb = mapCanvasEl.getBoundingClientRect();
    if (cb.width === 0 || cb.height === 0) return;

    // Normalise dot centres to viewBox units (0-100 X, 0-200 Y)
    const pts = Array.from(dots).map((d) => {
      const r = d.getBoundingClientRect();
      return {
        x: ((r.left + r.width / 2 - cb.left) / cb.width) * 100,
        y: ((r.top  + r.height / 2 - cb.top)  / cb.height) * 200,
      };
    });

    // Build path: M to first, then cubic beziers to each subsequent
    // dot. Control points sit at the same X as the dots (so the path
    // exits/enters each dot along the vertical axis) but bow out to
    // alternating sides between them — gives a Nordic-river feel.
    const segs = [`M ${pts[0].x.toFixed(2)} ${pts[0].y.toFixed(2)}`];
    for (let i = 1; i < pts.length; i++) {
      const a = pts[i - 1];
      const b = pts[i];
      // Bow direction alternates by segment index. Amplitude is in
      // viewBox X units (0-100) — clamped down on tall segments to
      // avoid the path drifting outside the canvas.
      const bowDir = (i % 2 === 1) ? 1 : -1;
      const bowAmount = Math.min(20, (b.y - a.y) * 0.18);
      const cx1 = 50 + bowAmount * bowDir;
      const cy1 = a.y + (b.y - a.y) * 0.35;
      const cx2 = 50 + bowAmount * bowDir;
      const cy2 = a.y + (b.y - a.y) * 0.65;
      segs.push(`C ${cx1.toFixed(2)} ${cy1.toFixed(2)}, ${cx2.toFixed(2)} ${cy2.toFixed(2)}, ${b.x.toFixed(2)} ${b.y.toFixed(2)}`);
    }
    const d = segs.join(' ');
    pathBg.setAttribute('d', d);
    pathDraw.setAttribute('d', d);

    // Re-measure the drawn path's length and reset the dash offset
    // so the draw-in animation covers the full new geometry.
    const len = pathDraw.getTotalLength();
    pathDraw.style.strokeDasharray = len;
    // If the scroll-trigger animation already played to completion,
    // keep the path drawn; otherwise hide it pending scroll.
    const trig = drawScrollTrigger;
    if (trig && trig.progress >= 1) {
      pathDraw.style.strokeDashoffset = 0;
    } else {
      pathDraw.style.strokeDashoffset = len;
    }
  }

  // Build initially after a paint
  requestAnimationFrame(buildMapPath);

  // Animate the accent path drawing in as the user scrolls down
  // through the meaning section
  if (pathDraw) {
    const tween = gsap.to(pathDraw, {
      strokeDashoffset: 0,
      ease: 'none',
      scrollTrigger: {
        trigger: '#bifrost-meaning',
        start: 'top 65%',
        end: 'bottom 75%',
        scrub: 0.6,
        invalidateOnRefresh: true,
        onRefresh: () => {
          // Re-measure dasharray on every ScrollTrigger refresh so
          // the animation stays in sync with any path changes
          const len = pathDraw.getTotalLength();
          pathDraw.style.strokeDasharray = len;
        },
      }
    });
    drawScrollTrigger = tween.scrollTrigger;
  }

  // Rebuild the path on resize (debounced) since dot positions move
  let mapPathResizeTimer;
  window.addEventListener('resize', () => {
    clearTimeout(mapPathResizeTimer);
    mapPathResizeTimer = setTimeout(() => {
      buildMapPath();
      ScrollTrigger.refresh();
    }, 220);
  });

  // Mobile fallback — the SVG path is hidden and replaced by a CSS
  // pseudo-element rail. Drive its progress with a CSS custom prop
  // so the same scroll range animates a vertical fill.
  const mapCanvas = document.querySelector('.map-canvas');
  if (mapCanvas) {
    const railObj = { p: 0 };
    gsap.to(railObj, {
      p: 100,
      ease: 'none',
      scrollTrigger: {
        trigger: '#bifrost-meaning',
        start: 'top 65%',
        end: 'bottom 75%',
        scrub: 0.6,
        onUpdate: () => {
          mapCanvas.style.setProperty('--rail-progress', railObj.p + '%');
        }
      }
    });
  }

  // Per-stop reveal — dot pops in first, then content + image rise
  // and fade in alongside each other. ToggleActions: play forward
  // when entering, reverse when scrolling back up past the trigger.
  gsap.utils.toArray('.map-stop').forEach((stop) => {
    const dot = stop.querySelector('.dot');
    const contentBits = stop.querySelectorAll('.stop-content > *');
    const image = stop.querySelector('.stop-image');

    const tl = gsap.timeline({
      scrollTrigger: {
        trigger: stop,
        start: 'top 78%',
        toggleActions: 'play none none reverse',
      }
    });

    // Dot pops in with a subtle back ease — feels like a pin
    // dropping into the map
    if (dot) {
      tl.to(dot, {
        scale: 1, opacity: 1,
        duration: 0.55, ease: 'back.out(2)',
      });
    }

    // Text bits stagger in
    if (contentBits.length) {
      tl.to(contentBits, {
        opacity: 1, y: 0,
        duration: 0.7, stagger: 0.08,
        ease: 'power3.out',
      }, '-=0.35');
    }

    // Image animates in alongside the text (overlapping for unity)
    if (image) {
      tl.to(image, {
        opacity: 1, y: 0,
        duration: 0.9,
        ease: 'power3.out',
      }, '-=0.6');
    }
  });

  /* SCENE 6 — Join CTA + Innovationsfonden footer: REMOVED 2026-05-19
     in the customer-presentation conversion. The CTA, confirmation
     panel, click handler, and three-mark footer all went away with
     the #bifrost-join section in protected/index.html. */

  /* -------------------------------------------------------------
     Refresh ScrollTrigger after fonts and images load so positions
     are accurate — large embedded illustrations affect layout.
     ------------------------------------------------------------- */
  if (document.fonts && document.fonts.ready) {
    document.fonts.ready.then(() => ScrollTrigger.refresh());
  }
  // Refresh once illustrations have laid out
  const illustrations = document.querySelectorAll('#bifrost-meaning img');
  let pending = illustrations.length;
  if (pending === 0) ScrollTrigger.refresh();
  illustrations.forEach((img) => {
    if (img.complete) {
      if (--pending === 0) ScrollTrigger.refresh();
    } else {
      img.addEventListener('load',  () => { if (--pending === 0) ScrollTrigger.refresh(); });
      img.addEventListener('error', () => { if (--pending === 0) ScrollTrigger.refresh(); });
    }
  });

    // ─── One consolidated resize handler ─────────────────────────
    // Site 2 had two separate resize listeners; we defer to ScrollTrigger's
    // own handling + our de-duped refresh. Scroller-relative measurements
    // get recalculated whenever ScrollTrigger.refresh fires.
    let resizeT = null;
    window.addEventListener('resize', () => {
      clearTimeout(resizeT);
      resizeT = setTimeout(scheduleRefresh, 220);
    });

    // After fonts load, re-measure (headline wrap can shift positions).
    if (document.fonts && document.fonts.ready) {
      document.fonts.ready.then(scheduleRefresh);
    }

    // After all illustrations load, re-measure (treasure-map stops change height).
    const bgIllustrations = document.querySelectorAll('#page-overview .stop-illust');
    let pendingBg = bgIllustrations.length;
    if (pendingBg === 0) scheduleRefresh();
    bgIllustrations.forEach((el) => {
      // Illustrations are CSS-background images; use an Image() to listen for load
      const bg = getComputedStyle(el).backgroundImage;
      const url = bg && bg.match(/url\("?([^")]+)"?\)/);
      if (!url) { if (--pendingBg === 0) scheduleRefresh(); return; }
      const img = new Image();
      img.onload = img.onerror = () => { if (--pendingBg === 0) scheduleRefresh(); };
      img.src = url[1];
    });

    // Final refresh after everything wires up
    scheduleRefresh();
  }

  /**
   * Smooth-scroll the Overview's internal scroller to a scene.
   * Called by the dot-nav click handler in timeline.js.
   *
   * @param {string} sceneId  id of the scene section (e.g. "bifrost")
   *                          — see sceneOrder[] inside init().
   *                          Special value "hero" scrolls to top (0).
   */
  // Per-scene scroll offsets. Added to the scene's offsetTop when a
  // dot-nav button anchors to it, so the reader lands AFTER the scene's
  // initial reveal rather than at an empty pre-scrub frame.
  //
  //   bifrost — section is 200vh with a scrubbed reveal that runs from
  //     top-top to bottom-bottom (100vh scroll range). The sub-headline
  //     fades in at ~0.83 of that. Offset is computed per viewport as
  //     85% of vh so the reader arrives on the fully-drawn arc +
  //     wordmark, regardless of display size.
  //
  //   platform-cards / platform-roadmap — pinned at 'center center', so
  //     the section's "intended landing" is the scroll position where
  //     section.centre aligns with viewport.centre. That position is
  //     section.offsetTop + (section.height - vh) / 2. For sections
  //     shorter than the viewport this offset is negative — the user
  //     lands just before the section's natural top, but the pin is
  //     engaged so visually they see the section centred at full
  //     opacity with the entire pin budget still ahead of them.
  //
  //   hero — short reveal tween; offsetTop is already the correct
  //     landing spot so offset is 0.
  function getSceneAnchorOffset(sceneId) {
    const vh = window.innerHeight;
    switch (sceneId) {
      case 'bifrost':
        return Math.round(vh * 0.85);
      case 'platform-cards':
      case 'platform-roadmap': {
        const el = document.getElementById(sceneId);
        if (!el) return 0;
        return Math.round((el.offsetHeight - vh) / 2);
      }
      default:
        return 0;
    }
  }

  // Section's offset within the scroller's content. Walks the
  // offsetParent chain summing offsetTop. Necessary because
  // ScrollTrigger's pinSpacing wraps pinned sections in a pin-spacer
  // div (position: relative), which becomes the section's offsetParent
  // — so `target.offsetTop` alone returns ~0 and scrollTo lands the
  // user at the top of the page instead of the requested section.
  function offsetTopWithin(el, scroller) {
    let offset = 0;
    let current = el;
    while (current && current !== scroller) {
      offset += current.offsetTop;
      const parent = current.offsetParent;
      if (!parent) break;
      current = parent;
    }
    return offset;
  }

  function scrollTo(sceneId) {
    if (!scrollerEl) return; // init() hasn't run yet — ignore
    const target = document.getElementById(sceneId);
    if (!target) return;

    // "hero" is the first scene and sits at scrollTop 0. Scrolling to
    // the scene element directly works in most cases but produces a tiny
    // non-zero offset (padding / border) — hard-code 0 for hero.
    const base = sceneId === 'hero' ? 0 : offsetTopWithin(target, scrollerEl);
    const scrollY = base + getSceneAnchorOffset(sceneId);

    if (lenisInstance && typeof lenisInstance.scrollTo === 'function') {
      // Lenis does the smooth animation. `immediate: false` uses the
      // same easing as wheel input — feels consistent.
      lenisInstance.scrollTo(scrollY, { immediate: false });
    } else {
      // Fallback for pre-init / reduced-motion: hard-jump.
      scrollerEl.scrollTo({ top: scrollY, behavior: 'smooth' });
    }
  }

  // Public surface — timeline.js calls these when the Overview tab
  // activates (init) or when a dot-nav button targeting a scene is
  // clicked (scrollTo).
  window.__bifrost = { init, scrollTo };
})();