/* One header system: primary links + collapsible chapter index. */
.site-header {
  transition: transform .35s ease, background-color .35s ease;
}

.salt-story-nav {
  top: 64px;
  padding: 10px 22px;
  max-height: 66px;
  transition: max-height .35s ease, padding .35s ease, transform .35s ease, opacity .3s ease;
}

body.chapter-nav-collapsed .site-header {
  transform: translateY(-64px);
}

body.chapter-nav-collapsed .salt-story-nav {
  top: 0;
  max-height: 42px;
  padding-top: 5px;
  padding-bottom: 5px;
}

body.chapter-nav-collapsed .salt-story-nav a {
  padding-top: 4px;
  padding-bottom: 4px;
}

.chapter-nav-toggle {
  position: sticky;
  top: 7px;
  z-index: 15;
  flex: 0 0 auto;
  width: 30px;
  height: 30px;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: #000;
  color: var(--ink);
  cursor: pointer;
}

.chapter-nav-toggle::before {
  content: "−";
}

body.chapter-nav-collapsed .chapter-nav-toggle::before {
  content: "+";
}

/* Restore the relations plate: no hand-off fade. */
#salt-relations .salt-media > img {
  transform: none !important;
  opacity: 1 !important;
  visibility: visible !important;
  filter: none !important;
}

/* Process film becomes image + editorial explanation. */
.salt-growth-video {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(240px, .65fr);
  gap: clamp(26px, 4vw, 56px);
  align-items: center;
}

.salt-growth-video video {
  grid-column: 1;
}

.salt-growth-video figcaption {
  position: static;
  grid-column: 2;
  display: block;
  max-width: 30ch;
  padding: 0;
  background: transparent;
  text-align: left;
}

.salt-growth-video figcaption strong {
  font-size: clamp(20px, 2.2vw, 30px);
  line-height: 1.1;
}

.salt-growth-video figcaption::after {
  content: "A time-compressed observation of crystals nucleating at the edge, dispersing across the liquid surface and accumulating into a visible field.";
  display: block;
  margin-top: 16px;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.55;
}

/* Editable missing-image slots used across chapters. */
.chapter-placeholder-grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: clamp(18px, 3vw, 38px);
  width: min(1040px, calc(100% - 44px));
  margin: clamp(42px, 7vw, 90px) auto 0;
}

.chapter-placeholder {
  grid-column: span 5;
  margin: 0;
  color: var(--muted);
}

.chapter-placeholder:nth-child(even) {
  grid-column: 8 / span 5;
  margin-top: clamp(50px, 8vw, 110px);
}

.chapter-placeholder-image {
  width: 100%;
  aspect-ratio: var(--placeholder-ratio, 4 / 5);
  background: #fff;
}

.chapter-placeholder figcaption {
  margin-top: 10px;
  font-size: 11px;
  line-height: 1.45;
}

.chapter-placeholder figcaption strong {
  display: block;
  margin-bottom: 3px;
  color: var(--ink);
  font-size: 10px;
  letter-spacing: .07em;
  text-transform: uppercase;
}

.chapter-placeholder--wide {
  grid-column: span 8;
}

.chapter-placeholder--wide .chapter-placeholder-image {
  --placeholder-ratio: 16 / 9;
}

.chapter-placeholder--square .chapter-placeholder-image {
  --placeholder-ratio: 1 / 1;
}

.chapter-placeholder--portrait .chapter-placeholder-image {
  --placeholder-ratio: 3 / 5;
}

@media (max-width: 760px) {
  .salt-growth-video { grid-template-columns: 1fr; }
  .salt-growth-video video,
  .salt-growth-video figcaption { grid-column: 1; }
  .chapter-placeholder,
  .chapter-placeholder:nth-child(even),
  .chapter-placeholder--wide { grid-column: 1 / -1; margin-top: 0; }
}

@media (prefers-reduced-motion: reduce) {
  .site-header,
  .salt-story-nav { transition: none; }
}