.chem-hero {
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
  padding: var(--space-7);
}

.crumbs {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  color: var(--color-muted);
  font-size: 13px;
  font-weight: 700;
}

.crumb-link {
  color: var(--color-brand-900);
  text-decoration: none;
}

.crumb-link:hover {
  text-decoration: underline;
}

.crumb-sep,
.crumb-current {
  color: var(--color-muted);
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.42fr) minmax(300px, 0.88fr);
  gap: var(--space-5);
  align-items: start;
}

.hero-copy,
.hero-rail,
.rail-card,
.exposure-card,
.core-card,
.interface-card,
.shell-card,
.doff-card,
.doff-step,
.heat-card,
.related-card {
  min-width: 0;
}

.hero-copy {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  padding: var(--space-5);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: #fbfcfb;
}

.hero-rail {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.rail-card {
  padding: var(--space-5);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: #ffffff;
}

.rail-card-contrast {
  background: var(--color-brand-200);
}

.rail-title,
.exposure-title,
.core-title,
.interface-title,
.shell-title,
.doff-title,
.doff-step-title,
.heat-title,
.related-title {
  margin: 0 0 var(--space-3) 0;
  font-size: 18px;
  font-weight: 900;
  color: var(--color-brand-900);
}

.exposure-band {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--space-4);
}

.exposure-card {
  padding: var(--space-4);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: #ffffff;
}

.exposure-text,
.core-text,
.shell-text,
.doff-text,
.doff-step-text,
.related-text {
  margin: 0;
  color: var(--color-muted);
  font-size: 14px;
  line-height: 1.75;
}

.chem-section {
  padding: var(--space-7);
  margin-top: var(--space-6);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.chem-section-core {
  background: linear-gradient(180deg, #ffffff 0%, #fbfcfb 100%);
}

.chem-section-shell {
  background: linear-gradient(180deg, #fbfcfb 0%, #ffffff 100%);
}

.chem-section-heat {
  background: linear-gradient(180deg, #ffffff 0%, #f6f8f5 100%);
}

.section-heading {
  margin: 0;
  font-family: Fraunces, Georgia, serif;
  font-size: 30px;
  line-height: 1.18;
  color: var(--color-brand-900);
}

.section-paragraph {
  margin: 0;
  color: var(--color-muted);
  font-size: 15px;
  line-height: 1.8;
}

.core-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: var(--space-4);
  margin-top: var(--space-2);
}

.core-card {
  padding: var(--space-5);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: #ffffff;
}

.core-card-highlight {
  background: var(--color-brand-200);
}

.interface-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.18fr) minmax(300px, 0.82fr);
  gap: var(--space-5);
  align-items: start;
}

.interface-main {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  min-width: 0;
}

.interface-side {
  min-width: 0;
}

.interface-card,
.heat-card {
  padding: var(--space-5);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: #fbfcfb;
}

.shell-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--space-4);
}

.shell-card {
  padding: var(--space-4);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: #ffffff;
}

.shell-note {
  margin-top: var(--space-2);
  padding: var(--space-4);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-brand-200);
}

.shell-note-text {
  margin: 0;
  color: var(--color-muted);
  font-size: 14px;
  line-height: 1.75;
}

.doff-layout {
  display: grid;
  grid-template-columns: minmax(300px, 0.8fr) minmax(0, 1.2fr);
  gap: var(--space-5);
  align-items: start;
}

.doff-side {
  min-width: 0;
}

.doff-main {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  min-width: 0;
}

.doff-card {
  padding: var(--space-5);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: #ffffff;
}

.doff-flow {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-4);
}

.doff-step {
  display: flex;
  gap: var(--space-3);
  padding: var(--space-4);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: #fbfcfb;
}

.doff-index {
  width: 38px;
  height: 38px;
  border-radius: 12px;
  background: var(--color-brand-200);
  color: var(--color-brand-900);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 900;
  flex: 0 0 auto;
}

.doff-body {
  min-width: 0;
}

.heat-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-5);
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--space-4);
  margin-top: var(--space-2);
}

.related-card {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding: var(--space-4);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: #ffffff;
  text-decoration: none;
}

.related-card:hover {
  border-color: var(--color-brand-900);
  transform: translateY(-1px);
}

.dense-list {
  margin: 0;
  padding-left: 20px;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  color: var(--color-muted);
  font-size: 14px;
  line-height: 1.7;
}

.nav-link.is-active {
  color: var(--color-brand-900);
  background: var(--color-brand-200);
}

.mobile-nav-link.is-active {
  background: var(--color-brand-200);
  border-color: var(--color-brand-200);
  color: var(--color-brand-900);
}

@media (max-width: 1180px) {
  .exposure-band,
  .shell-grid,
  .related-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .core-grid,
  .heat-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 980px) {
  .hero-grid,
  .interface-layout,
  .doff-layout,
  .doff-flow {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  .chem-hero,
  .chem-section {
    padding: var(--space-6);
  }

  .section-heading {
    font-size: 26px;
  }

  .exposure-band,
  .shell-grid,
  .related-grid {
    grid-template-columns: 1fr;
  }

  .hero-copy,
  .rail-card,
  .exposure-card,
  .core-card,
  .interface-card,
  .shell-card,
  .shell-note,
  .doff-card,
  .doff-step,
  .heat-card,
  .related-card {
    padding: var(--space-4);
  }
}