/* Scroll-scrub hero — ported from the design's React component.
 *
 * Single-scene variant: the journey is one continuous ~15s take, so there are no
 * connector segments, no layer crossfade and no chapter route nav. What remains
 * is a sticky stage with the film, and one liner-note chapter scrolling over it.
 */

.scroll-scrub {
  --ss-progress: 0;
  --ss-bg: var(--gf-ink);
  --ss-ink: var(--gf-paper);
  --ss-muted: #a8a196;
  --ss-accent: var(--gf-coral);
  position: relative;
  isolation: isolate;
  color: var(--ss-ink);
  background: var(--ss-bg);
}

.scroll-scrub__stage {
  position: sticky;
  top: 0;
  z-index: 0;
  width: 100%;
  /* svh, not dvh: dvh changes as the mobile URL bar hides, which resizes a
     sticky element mid-scroll and shifts the scroll-to-progress mapping under
     the gesture. The JS deliberately ignores that resize (see onResize), so the
     geometry it has cached would go stale. svh is constant. */
  height: 100svh;
  overflow: hidden;
  background: var(--ss-bg);
  /* Already overflow:hidden and a stacking context, so this adds no new
     constraint — it just lets the compositor bound damage to the stage. */
  contain: paint;
}

.scroll-scrub__media,
.scroll-scrub__layer,
.scroll-scrub__picture,
.scroll-scrub__poster,
.scroll-scrub__video {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.scroll-scrub__media {
  z-index: 0;
}

.scroll-scrub__layer {
  margin: 0;
  overflow: hidden;
}

.scroll-scrub__poster,
.scroll-scrub__video {
  display: block;
  object-fit: cover;
  object-position: var(--ss-object-position, 50% 50%);
}

.scroll-scrub__poster {
  z-index: 0;
}

.scroll-scrub__video {
  z-index: 1;
  /* Own layer, so decoding a new frame does not re-raster the story text
     stacked above it. The overlay fast-path is already off here — the video is
     occluded by .scroll-scrub__story — so promotion costs nothing it still had. */
  will-change: transform;
}

/* The poster is only hidden once the video has actually painted a frame,
   which is what the first `seeked` event tells us. Hiding it earlier shows
   a flash of empty video element. */
.scroll-scrub__layer[data-video-painted="true"] .scroll-scrub__poster {
  visibility: hidden;
}

.scroll-scrub__progress {
  position: absolute;
  z-index: 5;
  top: 0;
  right: 0;
  left: 0;
  height: 2px;
  background: rgba(247, 244, 238, 0.14);
  pointer-events: none;
}

.scroll-scrub__progress span {
  display: block;
  width: 100%;
  height: 100%;
  background: var(--ss-accent);
  transform: scaleX(var(--ss-progress));
  transform-origin: left center;
  will-change: transform;
}

.scroll-scrub__story {
  position: relative;
  z-index: 3;
  margin-top: -100svh;
  pointer-events: none;
}

.scroll-scrub__chapter {
  position: relative;
}

.scroll-scrub__chapter-pin {
  position: sticky;
  top: 0;
  display: flex;
  align-items: center;
  min-height: 100svh;
  padding: clamp(5rem, 9vw, 8rem) clamp(1.25rem, 6vw, 6rem);
  pointer-events: none;
}

.scroll-scrub__copy {
  position: relative;
  width: min(40rem, 48vw);
  pointer-events: auto;
}

/* Scrim so the copy stays readable over whatever frame is showing. */
.scroll-scrub__copy::before {
  position: absolute;
  z-index: -1;
  inset: -3rem -5rem;
  content: "";
  background: radial-gradient(
    ellipse at center,
    rgba(18, 17, 15, 0.88) 0%,
    rgba(18, 17, 15, 0.58) 52%,
    transparent 76%
  );
  pointer-events: none;
}

.scroll-scrub__kicker {
  max-width: 30ch;
  margin: 0 0 1rem;
  color: var(--ss-accent);
  font-family: var(--gf-mono);
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

.scroll-scrub__title {
  max-width: 15ch;
  margin: 0;
  color: var(--ss-ink);
  font-family: var(--gf-serif);
  font-weight: 400;
  font-size: clamp(2.75rem, 6vw, 6rem);
  line-height: 0.96;
  letter-spacing: -0.02em;
  text-wrap: balance;
}

.scroll-scrub__body {
  max-width: 42ch;
  margin: 1.5rem 0 0;
  color: var(--ss-muted);
  font-size: clamp(1rem, 1.35vw, 1.2rem);
  line-height: 1.55;
}

.scroll-scrub__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
  margin: 1.5rem 0 0;
  padding: 0;
  list-style: none;
}

.scroll-scrub__tags li {
  padding: 0.45rem 0.7rem;
  border: 1px solid rgba(247, 244, 238, 0.2);
  color: var(--ss-ink);
  font-family: var(--gf-mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.scroll-scrub__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 2rem;
}

.scroll-scrub__hint {
  position: absolute;
  z-index: 4;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  color: var(--ss-muted);
  font-family: var(--gf-mono);
  font-size: 0.62rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  pointer-events: none;
  transition: opacity 0.4s ease;
}

.scroll-scrub[data-scrolled="true"] .scroll-scrub__hint {
  opacity: 0;
}

@media (max-width: 860px) {
  .scroll-scrub__poster,
  .scroll-scrub__video {
    object-position: var(--ss-mobile-position, 50% 50%);
  }

  .scroll-scrub__chapter-pin {
    align-items: flex-end;
    justify-content: flex-start;
    padding: 6.5rem max(1.25rem, env(safe-area-inset-right))
      calc(4rem + env(safe-area-inset-bottom))
      max(1.25rem, env(safe-area-inset-left));
  }

  .scroll-scrub__copy {
    width: min(100%, 36rem);
  }

  .scroll-scrub__copy::before {
    inset: -3rem -2rem;
    background: linear-gradient(
      to top,
      var(--ss-bg) 0%,
      rgba(18, 17, 15, 0.82) 58%,
      transparent 100%
    );
  }

  .scroll-scrub__title {
    max-width: 14ch;
    font-size: clamp(2.3rem, 11vw, 4.5rem);
  }
}

@media (prefers-reduced-motion: reduce) {
  .scroll-scrub__chapter {
    min-height: 100svh !important;
  }

  .scroll-scrub__progress span {
    transition: none;
  }
}