/**
 * ============================================
 * AI Agency Framework — PILLAR PAGE STYLES
 * ============================================
 * Architectural Blueprint Aesthetic
 * /ai-impact/ — Topical Silo 01
 * ============================================
 */

/* ============================================
   1. BREADCRUMB
   ============================================ */
.breadcrumb {
  position: fixed;
  top: 72px;
  left: 0;
  right: 0;
  z-index: 299;
  background: rgba(10, 10, 15, 0.9);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-default);
  padding: var(--space-2) 0;
}

.breadcrumb__list {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  list-style: none;
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 0 var(--section-px);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--text-muted);
}

.breadcrumb__item:not(:last-child)::after {
  content: '/';
  margin-left: var(--space-2);
  color: var(--border-default);
}

.breadcrumb__link {
  color: var(--text-tertiary);
  text-decoration: none;
  transition: color 0.2s ease;
}

.breadcrumb__link:hover {
  color: var(--accent-primary);
}

/* ============================================
   2. PILLAR HERO (60vh)
   ============================================ */
.pillar-hero {
  position: relative;
  width: 100%;
  height: 60vh;
  min-height: 400px;
  display: flex;
  align-items: flex-end;
  overflow: hidden;
  background: var(--color-space-500);
}

.pillar-hero__canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
}

.pillar-hero__vignette {
  position: absolute;
  inset: 0;
  z-index: 2;
  background:
    radial-gradient(ellipse 70% 50% at 50% 100%, rgba(10, 10, 15, 0.3) 0%, transparent 60%),
    linear-gradient(to bottom, transparent 0%, rgba(10, 10, 15, 0.8) 100%);
  pointer-events: none;
}

.pillar-hero__content {
  position: relative;
  z-index: 10;
  width: 100%;
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 0 var(--section-px) var(--space-16);
}

.pillar-hero__eyebrow {
  margin-bottom: var(--space-4);
  opacity: 0.8;
}

.pillar-hero__title {
  margin: 0;
  font-family: var(--font-headline);
  font-weight: var(--weight-bold);
  line-height: var(--leading-none);
  letter-spacing: var(--tracking-tighter);
}

.pillar-hero__title-line {
  display: block;
  font-size: clamp(3.5rem, 9vw, 7rem);
  color: var(--text-primary);
}

.pillar-hero__title-line--accent {
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ============================================
   3. INTRODUCTION + STICKY TOC
   ============================================ */
.pillar-intro {
  padding: var(--section-py) 0;
  border-bottom: 1px solid var(--border-default);
}

.pillar-intro__grid {
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: var(--space-16);
  align-items: start;
}

.pillar-intro__content {
  display: flex;
  flex-direction: column;
  gap: var(--space-6);
}

.pillar-intro__lead {
  font-size: var(--text-xl);
  line-height: var(--leading-relaxed);
  color: var(--text-primary);
}

/* TOC Sidebar */
.pillar-toc {
  position: sticky;
  top: 120px;
}

.pillar-toc__inner {
  position: relative;
  background: var(--surface-glass);
  backdrop-filter: var(--blur-lg);
  border: 1px solid var(--border-default);
  border-radius: var(--card-radius);
  padding: var(--space-6);
}

.pillar-toc__title {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: var(--weight-medium);
  text-transform: uppercase;
  letter-spacing: var(--tracking-widest);
  color: var(--text-muted);
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-3);
  border-bottom: 1px solid var(--border-default);
}

.pillar-toc__list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.pillar-toc__link {
  display: block;
  padding: var(--space-2) var(--space-3);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: var(--radius-sm);
  transition: all 0.2s var(--ease-smooth);
  border-left: 2px solid transparent;
}

.pillar-toc__link:hover {
  color: var(--text-primary);
  background: var(--surface-hover);
}

.pillar-toc__link--active {
  color: var(--accent-primary);
  background: var(--surface-active);
  border-left-color: var(--accent-primary);
}

/* ============================================
   4. PILLAR SECTIONS
   ============================================ */
.pillar-section {
  position: relative;
  padding: var(--section-py) 0;
  border-bottom: 1px solid var(--border-default);
}

.pillar-section--parallax {
  min-height: 80vh;
  display: flex;
  align-items: center;
  overflow: hidden;
}

.pillar-section__bg {
  position: absolute;
  inset: -10%;
  z-index: 0;
  will-change: transform;
}

.pillar-section__bg img {
  width: 110%;
  height: 110%;
  object-fit: cover;
  opacity: 0.35;
}

.pillar-section__overlay {
  position: absolute;
  inset: 0;
  z-index: 1;
  background: linear-gradient(
    180deg,
    var(--bg-primary) 0%,
    rgba(10, 10, 15, 0.85) 20%,
    rgba(10, 10, 15, 0.85) 80%,
    var(--bg-primary) 100%
  );
}

.pillar-section__content {
  position: relative;
  z-index: 2;
}

.pillar-section__body {
  max-width: var(--content-narrow);
  margin-top: var(--space-8);
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
}

/* ============================================
   5. SCROLL-HIGHLIGHT TEXT EFFECT
   ============================================ */
[data-highlight-text] {
  background: linear-gradient(
    90deg,
    var(--accent-primary) 50%,
    var(--text-secondary) 50%
  );
  background-size: 200% 100%;
  background-position: 100% 0;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  transition: background-position 0.1s linear;
}

/* ============================================
   6. STATISTICS SECTION
   ============================================ */
.pillar-section--stats {
  background: var(--bg-secondary);
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
}

.stat-card {
  background: var(--surface-glass);
  backdrop-filter: var(--blur-lg);
  border: 1px solid var(--border-default);
  border-radius: var(--card-radius);
  padding: var(--space-8);
  text-align: center;
  transition: transform 0.3s var(--ease-cinematic),
              border-color 0.3s var(--ease-smooth),
              box-shadow 0.3s var(--ease-smooth);
}

.stat-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-hover);
  box-shadow: var(--shadow-elevated);
}

.stat-card__number {
  font-family: var(--font-headline);
  font-size: clamp(2.5rem, 5vw, 4rem);
  font-weight: var(--weight-bold);
  line-height: var(--leading-none);
  letter-spacing: var(--tracking-tighter);
  margin-bottom: var(--space-4);
}

.stat-card__prefix,
.stat-card__suffix {
  color: var(--accent-primary);
}

.stat-card__value {
  color: var(--text-primary);
}

.stat-card__label {
  font-size: var(--text-sm);
  color: var(--text-secondary);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-3);
}

.stat-card__source {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: var(--tracking-widest);
}

/* ============================================
   7. CLUSTER CARD STACK SYSTEM
   ============================================ */
.pillar-section--clusters {
  padding-bottom: 0;
}

.cluster-stack {
  position: relative;
  width: 100%;
  max-width: 1000px;
  margin: 0 auto;
  padding: 0 var(--section-px);
}

/* Individual Cluster Card */
.cluster-card {
  width: 100%;
  margin-bottom: var(--space-8);
  will-change: transform, opacity;
}

.cluster-card__inner {
  display: grid;
  grid-template-columns: 320px 1fr;
  background: var(--surface-glass);
  backdrop-filter: var(--blur-lg);
  border: 1px solid var(--border-default);
  border-radius: var(--card-radius);
  overflow: hidden;
  transition: border-color 0.3s var(--ease-smooth),
              box-shadow 0.3s var(--ease-smooth);
}

.cluster-card__inner:hover {
  border-color: var(--border-hover);
  box-shadow: var(--shadow-elevated);
}

.cluster-card__image {
  position: relative;
  overflow: hidden;
}

.cluster-card__image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.6s var(--ease-cinematic);
}

.cluster-card__inner:hover .cluster-card__image img {
  transform: scale(1.05);
}

.cluster-card__content {
  padding: var(--space-8);
  display: flex;
  flex-direction: column;
}

.cluster-card__meta {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  margin-bottom: var(--space-4);
}

.cluster-card__count {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: var(--tracking-widest);
}

.cluster-card__title {
  font-family: var(--font-headline);
  font-size: var(--text-2xl);
  font-weight: var(--weight-bold);
  color: var(--text-primary);
  margin-bottom: var(--space-3);
  line-height: var(--leading-tight);
}

.cluster-card__description {
  font-size: var(--text-sm);
  color: var(--text-secondary);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-6);
}

.cluster-card__preview {
  margin-top: auto;
  padding-top: var(--space-6);
  border-top: 1px solid var(--border-default);
}

.cluster-card__preview-title {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: var(--tracking-widest);
  margin-bottom: var(--space-3);
}

.cluster-card__spokes {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.cluster-card__spoke {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-2) var(--space-3);
  font-size: var(--text-sm);
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: var(--radius-sm);
  transition: all 0.2s var(--ease-smooth);
}

.cluster-card__spoke:hover {
  color: var(--accent-primary);
  background: var(--surface-active);
}

.cluster-card__spoke-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  background: var(--surface-active);
  border-radius: var(--radius-sm);
  color: var(--accent-primary);
  flex-shrink: 0;
}

.cluster-card__cta {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  margin-top: var(--space-6);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  color: var(--accent-primary);
  text-decoration: none;
  transition: gap 0.3s var(--ease-cinematic);
}

.cluster-card__cta:hover {
  gap: var(--space-3);
}

.cluster-card__cta svg {
  transition: transform 0.3s var(--ease-cinematic);
}

.cluster-card__cta:hover svg {
  transform: translateX(4px);
}

/* ============================================
   8. ARTICLE CARDS
   ============================================ */
.article-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
}

.article-card {
  background: var(--surface-glass);
  backdrop-filter: var(--blur-lg);
  border: 1px solid var(--border-default);
  border-radius: var(--card-radius);
  overflow: hidden;
  transition: transform 0.3s var(--ease-cinematic),
              border-color 0.3s var(--ease-smooth),
              box-shadow 0.3s var(--ease-smooth);
}

.article-card:hover {
  transform: translateY(-6px);
  border-color: var(--border-hover);
  box-shadow: var(--shadow-elevated);
}

.article-card__link {
  display: block;
  text-decoration: none;
  color: inherit;
}

.article-card__image {
  aspect-ratio: 16 / 9;
  overflow: hidden;
}

.article-card__image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.6s var(--ease-cinematic);
}

.article-card:hover .article-card__image img {
  transform: scale(1.08);
}

.article-card__content {
  padding: var(--space-6);
}

.article-card__meta {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
}

.article-card__title {
  font-family: var(--font-headline);
  font-size: var(--text-lg);
  font-weight: var(--weight-semibold);
  color: var(--text-primary);
  line-height: var(--leading-snug);
  margin-bottom: var(--space-2);
}

.article-card__excerpt {
  font-size: var(--text-sm);
  color: var(--text-secondary);
  line-height: var(--leading-relaxed);
}

/* ============================================
   9. FOOTER
   ============================================ */
.pillar-footer {
  padding: var(--space-12) 0;
  border-top: 1px solid var(--border-default);
}

.pillar-footer__grid {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.pillar-footer__nav {
  display: flex;
  gap: var(--space-6);
}

.pillar-footer__link {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: var(--tracking-widest);
  text-decoration: none;
  transition: color 0.2s ease;
}

.pillar-footer__link:hover {
  color: var(--accent-primary);
}

/* ============================================
   10. RESPONSIVE
   ============================================ */
@media (max-width: 1024px) {
  .pillar-intro__grid {
    grid-template-columns: 1fr;
  }

  .pillar-toc {
    position: relative;
    top: 0;
    order: -1;
  }

  .pillar-toc__inner {
    padding: var(--space-4);
  }

  .pillar-toc__list {
    flex-direction: row;
    flex-wrap: wrap;
    gap: var(--space-2);
  }

  .pillar-toc__link {
    border-left: none;
    border-bottom: 2px solid transparent;
    white-space: nowrap;
  }

  .pillar-toc__link--active {
    border-left-color: transparent;
    border-bottom-color: var(--accent-primary);
  }

  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .cluster-card__inner {
    grid-template-columns: 1fr;
  }

  .cluster-card__image {
    aspect-ratio: 16 / 9;
    max-height: 200px;
  }

  .article-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .breadcrumb {
    top: 64px;
  }

  .pillar-hero {
    height: 50vh;
  }

  .pillar-hero__title-line {
    font-size: clamp(2.5rem, 10vw, 4rem);
  }

  .stats-grid {
    grid-template-columns: 1fr;
  }

  .article-grid {
    grid-template-columns: 1fr;
  }

  .pillar-footer__grid {
    flex-direction: column;
    gap: var(--space-6);
    text-align: center;
  }

  .pillar-footer__nav {
    flex-wrap: wrap;
    justify-content: center;
  }
}

/* ============================================
   11. REDUCED MOTION
   ============================================ */
@media (prefers-reduced-motion: reduce) {
  [data-highlight-text] {
    background: none;
    -webkit-text-fill-color: var(--text-secondary);
  }

  .stat-card,
  .article-card,
  .cluster-card__inner {
    transition: none;
  }

  .stat-card:hover,
  .article-card:hover {
    transform: none;
  }
}