/* Chapter progress presentation and reduced-motion behavior. */

.scene-thread {
  display: block;
  inline-size: 100%;
  block-size: 2px;
  margin-block-end: clamp(var(--space-text), 3vw, 2.5rem);
  background: color-mix(in srgb, currentColor 16%, transparent);
  pointer-events: none;
}

.scene-thread::after {
  content: "";
  display: block;
  inline-size: 100%;
  block-size: 100%;
  background: var(--color-brand-signal);
  transform: scaleX(var(--chapter-progress, 1));
  transform-origin: left;
}

@media (prefers-reduced-motion: no-preference) {
  .chapter-arriving {
    animation: chapter-arrival 540ms ease-out both;
  }
  @keyframes chapter-arrival {
    from {
      opacity: 0.82;
      transform: translateY(12px);
    }
    to {
      opacity: 1;
      transform: translateY(0);
    }
  }
}

@media (prefers-reduced-motion: reduce) {
  .scene-thread::after {
    transform: none;
  }
}

/* Article progress runs alongside the existing chapter links. */

.article-toc nav[data-reading-track] {
  position: relative;
  border-inline-start: 3px solid #d8d5eb;
}

.article-toc nav[data-reading-track]::before {
  content: "";
  position: absolute;
  inset-block: 0;
  inset-inline-start: 0;
  width: 3px;
  background: var(--color-brand-primary);
  transform: scaleY(var(--reading-progress, 0));
  transform-origin: top;
  pointer-events: none;
}

@media (prefers-reduced-motion: reduce) {
  .article-toc nav[data-reading-track]::before {
    transform: none;
  }
}

.redesign.agency .article-toc nav a[data-toc]:is(.active, :hover, :focus-visible) {
  background: transparent;
  border-color: transparent;
  border-radius: 0;
  box-shadow: none;
  color: var(--color-blueprint-ink);
  text-decoration: underline;
  text-underline-offset: 0.16em;
}