.chapter-shell {
  max-width: 960px;
  margin: 0 auto;
  padding: 2rem 1rem 4rem;
  color: #e8e8ef;
  font-family: Inter, system-ui, sans-serif;
}

.chapter-shell__header h1 {
  font-size: clamp(2rem, 3vw, 3rem);
  margin: 0;
}

.chapter-shell__thesis {
  font-size: 1.125rem;
  opacity: 0.9;
}

.chapter-shell__section {
  margin-top: 2rem;
  padding: 1.25rem;
  background: rgba(24, 24, 40, 0.6);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 12px;
}

.chapter-shell__terms {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.chapter-shell__viz iframe {
  width: 100%;
  min-height: 560px;
  border: 0;
  border-radius: 10px;
  background: #0f0f1f;
}

@media (prefers-reduced-motion: reduce) {
  * {
    scroll-behavior: auto;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

.chapter-shell__viz-fallback { padding: 1rem; border: 1px dashed rgba(255,255,255,0.24); border-radius: 8px; background: rgba(0,0,0,0.2); }