/* Principle AI — pai.css
   Brand prefix: pai
   Theme: dark-ink with restrained teal accent
   Typography: IBM Plex Serif (headings) / IBM Plex Sans (body) / IBM Plex Mono (labels)
   Base unit: 8px
*/

/* ─── Custom Properties ───────────────────────────────────────────────── */
:root {
  --pai-bg-primary:     #0D1117;
  --pai-bg-secondary:   #161B22;
  --pai-bg-surface:     #1C2330;
  --pai-text-primary:   #E6EDF3;
  --pai-text-secondary: #8B949E;
  --pai-text-muted:     #484F58;
  --pai-accent:         #4A9EBE;
  --pai-accent-hover:   #3A8CAA;
  --pai-accent-dim:     #2D7A9A;
  --pai-accent-on-dark: #7DD3FC;
  --pai-border:         #21262D;
  --pai-border-subtle:  #1C2330;
  --pai-surface-hi:     #1F2A3C;
  --pai-cta-bg:         #4A9EBE;
  --pai-cta-text:       #0D1117;
  --pai-cta-hover:      #3A8CAA;

  --pai-font-serif: 'IBM Plex Serif', Georgia, 'Times New Roman', serif;
  --pai-font-sans:  'IBM Plex Sans', system-ui, -apple-system, sans-serif;
  --pai-font-mono:  'IBM Plex Mono', 'Courier New', monospace;

  --pai-radius:     4px;
  --pai-radius-sm:  2px;
  --pai-content-w:  1200px;
  --pai-prose-w:    720px;

  --pai-section-pad-v: 96px;
  --pai-section-pad-sm: 56px;
}

/* ─── Reset ───────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; }

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  padding: 0;
  background: var(--pai-bg-primary);
  color: var(--pai-text-primary);
  font-family: var(--pai-font-sans);
  font-size: 1rem;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

body.pai-cookie-visible {
  padding-bottom: 72px;
}

img, svg { display: block; max-width: 100%; }

a {
  color: var(--pai-accent-on-dark);
  text-decoration: none;
}

a:hover { text-decoration: underline; }

h1, h2, h3, h4, h5, h6 {
  font-family: var(--pai-font-serif);
  font-weight: 500;
  line-height: 1.25;
  margin: 0 0 0.75em;
  color: var(--pai-text-primary);
}

h1 { font-size: clamp(2rem, 4vw, 3rem); font-weight: 400; }
h2 { font-size: clamp(1.5rem, 3vw, 2.25rem); }
h3 { font-size: clamp(1.125rem, 2vw, 1.5rem); }
h4 { font-size: 1.125rem; font-family: var(--pai-font-sans); font-weight: 500; }

p { margin: 0 0 1em; }

ul, ol { margin: 0 0 1em; padding-left: 1.5em; }
li { margin-bottom: 0.35em; }

code, kbd, samp {
  font-family: var(--pai-font-mono);
  font-size: 0.875em;
  color: var(--pai-accent-on-dark);
  background: var(--pai-bg-surface);
  padding: 0.1em 0.3em;
  border-radius: var(--pai-radius-sm);
}

/* ─── Layout Utility ─────────────────────────────────────────────────── */
.pai-container {
  max-width: var(--pai-content-w);
  margin: 0 auto;
  padding: 0 24px;
}

.pai-prose {
  max-width: var(--pai-prose-w);
}

/* ─── Nav ─────────────────────────────────────────────────────────────── */
.pai-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 900;
  background: transparent;
  border-bottom: 1px solid transparent;
  transition: background 0.2s ease, border-color 0.2s ease;
}

.pai-nav--scrolled,
.pai-nav--solid {
  background: var(--pai-bg-primary);
  border-bottom-color: var(--pai-border);
}

.pai-nav__inner {
  max-width: var(--pai-content-w);
  margin: 0 auto;
  padding: 0 24px;
  height: 64px;
  display: flex;
  align-items: center;
  gap: 40px;
}

.pai-nav__logo {
  display: flex;
  align-items: center;
  text-decoration: none;
  flex-shrink: 0;
}

.pai-nav__logo img {
  height: 28px;
  width: auto;
  max-width: 200px;
}

.pai-nav__links {
  display: flex;
  align-items: center;
  gap: 8px;
  list-style: none;
  margin: 0;
  padding: 0;
  flex: 1;
}

.pai-nav__link {
  color: var(--pai-text-secondary);
  font-family: var(--pai-font-sans);
  font-size: 0.9rem;
  font-weight: 400;
  padding: 6px 12px;
  border-radius: var(--pai-radius);
  text-decoration: none;
  transition: color 0.15s;
  white-space: nowrap;
}

.pai-nav__link:hover {
  color: var(--pai-text-primary);
  text-decoration: none;
}

.pai-nav__link--active {
  color: var(--pai-text-primary);
}

.pai-nav__cta {
  margin-left: auto;
  flex-shrink: 0;
  display: inline-flex;
  align-items: center;
  padding: 8px 20px;
  background: transparent;
  border: 1px solid var(--pai-accent);
  border-radius: 20px;
  color: var(--pai-accent-on-dark);
  font-family: var(--pai-font-sans);
  font-size: 0.875rem;
  font-weight: 500;
  text-decoration: none;
  transition: background 0.15s, color 0.15s;
  white-space: nowrap;
}

.pai-nav__cta:hover {
  background: var(--pai-accent);
  color: var(--pai-cta-text);
  text-decoration: none;
}

.pai-nav__hamburger {
  display: none;
  background: transparent;
  border: none;
  padding: 6px;
  cursor: pointer;
  color: var(--pai-text-primary);
  margin-left: auto;
}

.pai-nav__hamburger svg {
  width: 22px;
  height: 22px;
  display: block;
}

.pai-nav__mobile {
  display: none;
  position: fixed;
  top: 64px;
  left: 0;
  right: 0;
  background: var(--pai-bg-secondary);
  border-bottom: 1px solid var(--pai-border);
  padding: 16px 24px 24px;
  z-index: 899;
  flex-direction: column;
  gap: 4px;
}

.pai-nav__mobile.is-open { display: flex; }

.pai-nav__mobile-link {
  color: var(--pai-text-secondary);
  font-size: 0.95rem;
  padding: 10px 0;
  border-bottom: 1px solid var(--pai-border);
  text-decoration: none;
  transition: color 0.15s;
}

.pai-nav__mobile-link:hover,
.pai-nav__mobile-link:last-child { color: var(--pai-text-primary); }
.pai-nav__mobile-link:last-child { border-bottom: none; }

.pai-nav__mobile-cta {
  margin-top: 12px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 20px;
  background: transparent;
  border: 1px solid var(--pai-accent);
  border-radius: 20px;
  color: var(--pai-accent-on-dark);
  font-size: 0.9rem;
  font-weight: 500;
  text-decoration: none;
  text-align: center;
  transition: background 0.15s, color 0.15s;
}

.pai-nav__mobile-cta:hover {
  background: var(--pai-accent);
  color: var(--pai-cta-text);
  text-decoration: none;
}

@media (max-width: 860px) {
  .pai-nav__links { display: none; }
  .pai-nav__cta { display: none; }
  .pai-nav__hamburger { display: flex; }
}

/* ─── Logo SVG ───────────────────────────────────────────────────────── */
.pai-logo-svg {
  display: block;
}

/* ─── Hero (Index) ───────────────────────────────────────────────────── */
.pai-hero {
  min-height: 100vh;
  background: var(--pai-bg-primary);
  display: flex;
  align-items: center;
  padding-top: 64px;
  position: relative;
  overflow: hidden;
}

.pai-hero__inner {
  max-width: var(--pai-content-w);
  margin: 0 auto;
  padding: 80px 24px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
  width: 100%;
}

.pai-hero__text { max-width: 560px; }

.pai-hero__eyebrow {
  font-family: var(--pai-font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--pai-accent);
  margin-bottom: 24px;
  display: block;
}

.pai-hero__headline {
  font-family: var(--pai-font-serif);
  font-size: clamp(2.25rem, 4.5vw, 3.5rem);
  font-weight: 400;
  line-height: 1.15;
  color: var(--pai-text-primary);
  margin: 0 0 24px;
}

.pai-hero__subhead {
  font-family: var(--pai-font-sans);
  font-size: 1.0625rem;
  line-height: 1.7;
  color: var(--pai-text-secondary);
  margin: 0 0 40px;
  max-width: 500px;
}

.pai-hero__actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  align-items: center;
}

.pai-hero__visual {
  display: flex;
  align-items: center;
  justify-content: center;
}

.pai-hero__svg {
  width: 100%;
  max-width: 520px;
  height: auto;
}

@media (max-width: 900px) {
  .pai-hero__inner {
    grid-template-columns: 1fr;
    gap: 48px;
    padding: 64px 24px;
  }
  .pai-hero__text { max-width: 100%; }
  .pai-hero__visual { display: none; }
}

/* ─── Sub-page Hero ──────────────────────────────────────────────────── */
.pai-subhero {
  background: var(--pai-bg-primary);
  padding-top: 128px;
  padding-bottom: 56px;
  border-bottom: 1px solid var(--pai-border);
}

.pai-subhero__inner {
  max-width: var(--pai-content-w);
  margin: 0 auto;
  padding: 0 24px;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 40px;
  align-items: end;
}

.pai-subhero__text { max-width: 680px; }

.pai-subhero__eyebrow {
  font-family: var(--pai-font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--pai-accent);
  display: block;
  margin-bottom: 16px;
}

.pai-subhero__title {
  font-family: var(--pai-font-serif);
  font-size: clamp(1.75rem, 3.5vw, 2.75rem);
  font-weight: 400;
  line-height: 1.2;
  color: var(--pai-text-primary);
  margin: 0 0 16px;
}

.pai-subhero__lede {
  font-size: 1rem;
  line-height: 1.7;
  color: var(--pai-text-secondary);
  margin: 0;
  max-width: 600px;
}

.pai-subhero__ornament {
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0.35;
  flex-shrink: 0;
}

@media (max-width: 700px) {
  .pai-subhero__inner { grid-template-columns: 1fr; }
  .pai-subhero__ornament { display: none; }
}

/* ─── Buttons ─────────────────────────────────────────────────────────── */
.pai-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 20px;
  font-family: var(--pai-font-sans);
  font-size: 0.9rem;
  font-weight: 500;
  text-decoration: none;
  cursor: pointer;
  border: none;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
  white-space: nowrap;
}

.pai-btn--primary {
  background: var(--pai-cta-bg);
  color: var(--pai-cta-text);
}

.pai-btn--primary:hover {
  background: var(--pai-cta-hover);
  color: var(--pai-cta-text);
  text-decoration: none;
}

.pai-btn--outline {
  background: transparent;
  border: 1px solid var(--pai-border);
  color: var(--pai-text-secondary);
}

.pai-btn--outline:hover {
  border-color: var(--pai-accent);
  color: var(--pai-accent-on-dark);
  text-decoration: none;
}

.pai-btn--ghost {
  background: transparent;
  border: none;
  color: var(--pai-accent-on-dark);
  padding: 12px 0;
  gap: 8px;
}

.pai-btn--ghost:hover {
  color: var(--pai-text-primary);
  text-decoration: none;
}

/* ─── Section Shared ──────────────────────────────────────────────────── */
.pai-section {
  padding: var(--pai-section-pad-v) 0;
}

.pai-section--alt {
  background: var(--pai-bg-secondary);
}

.pai-section--surface {
  background: var(--pai-bg-surface);
}

.pai-section__header {
  margin-bottom: 56px;
}

.pai-section__eyebrow {
  font-family: var(--pai-font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--pai-accent);
  display: block;
  margin-bottom: 12px;
}

.pai-section__title {
  font-family: var(--pai-font-serif);
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  font-weight: 400;
  color: var(--pai-text-primary);
  margin: 0 0 16px;
}

.pai-section__lede {
  font-size: 1rem;
  line-height: 1.7;
  color: var(--pai-text-secondary);
  max-width: 600px;
  margin: 0;
}

/* ─── Three Pillars ───────────────────────────────────────────────────── */
.pai-pillars {
  background: var(--pai-bg-secondary);
  padding: var(--pai-section-pad-v) 0;
}

.pai-pillars__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.pai-pillar {
  background: var(--pai-bg-primary);
  border: 1px solid var(--pai-border);
  border-radius: var(--pai-radius);
  padding: 36px 32px;
  transition: border-color 0.2s;
}

.pai-pillar:hover {
  border-color: var(--pai-accent-dim);
}

.pai-pillar__icon {
  width: 40px;
  height: 40px;
  margin-bottom: 20px;
  color: var(--pai-accent);
  font-size: 1.25rem;
  display: flex;
  align-items: center;
}

.pai-pillar__icon i {
  font-size: 1.25rem;
  color: var(--pai-accent);
}

.pai-pillar__heading {
  font-family: var(--pai-font-serif);
  font-size: 1.125rem;
  font-weight: 500;
  color: var(--pai-text-primary);
  margin: 0 0 12px;
}

.pai-pillar__body {
  font-size: 0.9375rem;
  line-height: 1.65;
  color: var(--pai-text-secondary);
  margin: 0;
}

@media (max-width: 800px) {
  .pai-pillars__grid { grid-template-columns: 1fr; }
}

/* ─── Methodology Strip ───────────────────────────────────────────────── */
.pai-methodology-strip {
  background: var(--pai-bg-surface);
  padding: var(--pai-section-pad-v) 0;
}

.pai-methodology-strip__inner {
  max-width: var(--pai-content-w);
  margin: 0 auto;
  padding: 0 24px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 72px;
  align-items: center;
}

.pai-methodology-strip__text { max-width: 520px; }

.pai-methodology-strip__visual {
  border-radius: var(--pai-radius);
  overflow: hidden;
  border: 1px solid var(--pai-border);
  background: var(--pai-bg-secondary);
}

.pai-methodology-strip__visual img {
  width: 100%;
  height: auto;
  display: block;
}

@media (max-width: 860px) {
  .pai-methodology-strip__inner {
    grid-template-columns: 1fr;
    gap: 40px;
  }
}

/* ─── Use Cases Trio ──────────────────────────────────────────────────── */
.pai-use-cases {
  background: var(--pai-bg-primary);
  padding: var(--pai-section-pad-v) 0;
}

.pai-use-cases__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.pai-use-case-card {
  background: var(--pai-bg-secondary);
  border: 1px solid var(--pai-border);
  border-radius: var(--pai-radius);
  padding: 32px 28px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  text-decoration: none;
  transition: border-color 0.2s, background 0.2s;
}

.pai-use-case-card:hover {
  border-color: var(--pai-accent-dim);
  background: var(--pai-surface-hi);
  text-decoration: none;
}

.pai-use-case-card__icon {
  color: var(--pai-accent);
  font-size: 1.25rem;
}

.pai-use-case-card__label {
  font-family: var(--pai-font-serif);
  font-size: 1.0625rem;
  font-weight: 500;
  color: var(--pai-text-primary);
  margin: 0;
  line-height: 1.3;
}

.pai-use-case-card__desc {
  font-size: 0.875rem;
  color: var(--pai-text-secondary);
  line-height: 1.6;
  margin: 0;
  flex: 1;
}

.pai-use-case-card__arrow {
  font-size: 0.8rem;
  color: var(--pai-accent);
  margin-top: auto;
  font-family: var(--pai-font-mono);
}

@media (max-width: 800px) {
  .pai-use-cases__grid { grid-template-columns: 1fr; }
}

/* ─── Research Cards ──────────────────────────────────────────────────── */
.pai-research-latest {
  background: var(--pai-bg-secondary);
  padding: var(--pai-section-pad-v) 0;
}

.pai-research-latest__header {
  max-width: var(--pai-content-w);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 40px;
  gap: 24px;
}

.pai-research-latest__grid {
  max-width: var(--pai-content-w);
  margin: 0 auto;
  padding: 0 24px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.pai-article-card {
  background: var(--pai-bg-primary);
  border: 1px solid var(--pai-border);
  border-radius: var(--pai-radius);
  padding: 28px 24px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  transition: border-color 0.2s;
}

.pai-article-card:hover { border-color: var(--pai-accent-dim); }

.pai-article-card__meta {
  display: flex;
  align-items: center;
  gap: 12px;
}

.pai-article-card__date {
  font-family: var(--pai-font-mono);
  font-size: 0.75rem;
  color: var(--pai-text-muted);
}

.pai-article-card__category {
  font-family: var(--pai-font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--pai-text-secondary);
}

.pai-article-card__title {
  font-family: var(--pai-font-serif);
  font-size: 1.0625rem;
  font-weight: 500;
  color: var(--pai-text-primary);
  line-height: 1.4;
  margin: 0;
}

.pai-article-card__abstract {
  font-size: 0.875rem;
  line-height: 1.65;
  color: var(--pai-text-secondary);
  margin: 0;
  flex: 1;
}

.pai-article-card__link {
  font-family: var(--pai-font-sans);
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--pai-accent-on-dark);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: auto;
  padding-top: 8px;
  border-top: 1px solid var(--pai-border);
}

.pai-article-card__link:hover { text-decoration: underline; }

@media (max-width: 900px) {
  .pai-research-latest__grid { grid-template-columns: 1fr; }
}

/* ─── CTA Band ────────────────────────────────────────────────────────── */
.pai-cta-band {
  background: var(--pai-surface-hi);
  padding: var(--pai-section-pad-v) 0;
  text-align: center;
  border-top: 1px solid var(--pai-border);
  border-bottom: 1px solid var(--pai-border);
}

.pai-cta-band__inner {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 24px;
}

.pai-cta-band__title {
  font-family: var(--pai-font-serif);
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  font-weight: 400;
  color: var(--pai-text-primary);
  margin: 0 0 20px;
}

.pai-cta-band__body {
  font-size: 1rem;
  line-height: 1.7;
  color: var(--pai-text-secondary);
  margin: 0 0 36px;
}

/* ─── Footer ─────────────────────────────────────────────────────────── */
.pai-footer {
  background: var(--pai-bg-secondary);
  border-top: 1px solid var(--pai-border);
  padding: 72px 0 0;
}

.pai-footer__inner {
  max-width: var(--pai-content-w);
  margin: 0 auto;
  padding: 0 24px;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 48px;
}

.pai-footer__brand { max-width: 360px; }

.pai-footer__logo {
  margin-bottom: 16px;
  display: block;
  text-decoration: none;
}

.pai-footer__logo img {
  height: 24px;
  width: auto;
  max-width: 180px;
}

.pai-footer__desc {
  font-size: 0.875rem;
  line-height: 1.65;
  color: var(--pai-text-secondary);
  margin: 0 0 16px;
}

.pai-footer__contact {
  font-size: 0.8125rem;
  color: var(--pai-text-muted);
  line-height: 1.6;
}

.pai-footer__contact a {
  color: var(--pai-text-muted);
  transition: color 0.15s;
}

.pai-footer__contact a:hover { color: var(--pai-accent-on-dark); text-decoration: none; }

.pai-footer__col-heading {
  font-family: var(--pai-font-sans);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--pai-text-muted);
  margin: 0 0 16px;
}

.pai-footer__col-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.pai-footer__col-links a {
  font-size: 0.875rem;
  color: var(--pai-text-secondary);
  text-decoration: none;
  transition: color 0.15s;
}

.pai-footer__col-links a:hover {
  color: var(--pai-text-primary);
  text-decoration: none;
}

.pai-footer__legal {
  max-width: var(--pai-content-w);
  margin: 56px auto 0;
  padding: 20px 24px;
  border-top: 1px solid var(--pai-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.pai-footer__copyright {
  font-size: 0.8rem;
  color: var(--pai-text-muted);
}

.pai-footer__legal-links {
  display: flex;
  gap: 20px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.pai-footer__legal-links a {
  font-size: 0.8rem;
  color: var(--pai-text-muted);
  text-decoration: none;
  transition: color 0.15s;
}

.pai-footer__legal-links a:hover { color: var(--pai-text-secondary); }

@media (max-width: 800px) {
  .pai-footer__inner { grid-template-columns: 1fr; gap: 32px; }
  .pai-footer__legal { flex-direction: column; align-items: flex-start; }
}

/* ─── Cookie Banner ──────────────────────────────────────────────────── */
.pai-cookie {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 950;
  background: var(--pai-bg-surface);
  border-top: 1px solid var(--pai-border);
  padding: 16px 24px;
  display: none;
}

.pai-cookie.is-visible { display: flex; }

.pai-cookie__inner {
  max-width: var(--pai-content-w);
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 24px;
  flex-wrap: wrap;
  width: 100%;
}

.pai-cookie__text {
  flex: 1;
  font-size: 0.8125rem;
  color: var(--pai-text-secondary);
  line-height: 1.5;
  min-width: 200px;
}

.pai-cookie__text a {
  color: var(--pai-accent-on-dark);
}

.pai-cookie__actions {
  display: flex;
  gap: 12px;
  flex-shrink: 0;
  flex-wrap: wrap;
}

.pai-cookie__btn {
  padding: 8px 18px;
  border-radius: 20px;
  font-family: var(--pai-font-sans);
  font-size: 0.8125rem;
  font-weight: 500;
  cursor: pointer;
  border: none;
  transition: background 0.15s, color 0.15s;
  white-space: nowrap;
}

.pai-cookie__btn--accept {
  background: var(--pai-cta-bg);
  color: var(--pai-cta-text);
}

.pai-cookie__btn--accept:hover { background: var(--pai-cta-hover); }

.pai-cookie__btn--essential {
  background: transparent;
  border: 1px solid var(--pai-border);
  color: var(--pai-text-secondary);
}

.pai-cookie__btn--essential:hover {
  border-color: var(--pai-accent-dim);
  color: var(--pai-text-primary);
}

/* ─── Feature List ───────────────────────────────────────────────────── */
.pai-feature-list {
  list-style: none;
  margin: 0 0 32px;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.pai-feature-list li {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  font-size: 0.9375rem;
  color: var(--pai-text-secondary);
  line-height: 1.6;
}

.pai-feature-list li::before {
  content: '';
  display: inline-block;
  width: 6px;
  height: 6px;
  background: var(--pai-accent);
  border-radius: 50%;
  flex-shrink: 0;
  margin-top: 7px;
}

/* ─── Two Column Text ─────────────────────────────────────────────────── */
.pai-two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: start;
}

.pai-two-col--center { align-items: center; }

@media (max-width: 800px) {
  .pai-two-col { grid-template-columns: 1fr; gap: 40px; }
}

/* ─── Prose Section ───────────────────────────────────────────────────── */
.pai-prose-section {
  padding: 56px 0;
  border-bottom: 1px solid var(--pai-border);
}

.pai-prose-section:last-of-type { border-bottom: none; }

.pai-prose-section__heading {
  font-family: var(--pai-font-serif);
  font-size: clamp(1.25rem, 2.5vw, 1.75rem);
  font-weight: 500;
  color: var(--pai-text-primary);
  margin: 0 0 20px;
}

.pai-prose-section__body {
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--pai-text-secondary);
  max-width: var(--pai-prose-w);
}

.pai-prose-section__body p { margin: 0 0 1em; }
.pai-prose-section__body ul { padding-left: 1.5em; }
.pai-prose-section__body li { margin-bottom: 0.5em; }

/* ─── Research Listing ────────────────────────────────────────────────── */
.pai-research-listing {
  background: var(--pai-bg-primary);
  padding: var(--pai-section-pad-v) 0;
}

.pai-research-grid {
  max-width: var(--pai-content-w);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  flex-direction: column;
  gap: 0;
}

.pai-research-item {
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 32px;
  padding: 36px 0;
  border-bottom: 1px solid var(--pai-border);
  align-items: start;
}

.pai-research-item:last-child { border-bottom: none; }

.pai-research-item__meta {
  padding-top: 4px;
}

.pai-research-item__date {
  font-family: var(--pai-font-mono);
  font-size: 0.8rem;
  color: var(--pai-text-muted);
  display: block;
  margin-bottom: 8px;
}

.pai-research-item__category {
  font-family: var(--pai-font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--pai-text-secondary);
}

.pai-research-item__content { flex: 1; }

.pai-research-item__title {
  font-family: var(--pai-font-serif);
  font-size: 1.1875rem;
  font-weight: 500;
  color: var(--pai-text-primary);
  margin: 0 0 12px;
  line-height: 1.35;
}

.pai-research-item__abstract {
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--pai-text-secondary);
  margin: 0 0 16px;
  max-width: 640px;
}

.pai-research-item__link {
  font-family: var(--pai-font-sans);
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--pai-accent-on-dark);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.pai-research-item__link:hover { text-decoration: underline; }

@media (max-width: 700px) {
  .pai-research-item { grid-template-columns: 1fr; gap: 12px; }
}

/* ─── Article Page ────────────────────────────────────────────────────── */
.pai-article-cover {
  width: 100%;
  max-height: 420px;
  object-fit: cover;
  border-radius: var(--pai-radius);
  border: 1px solid var(--pai-border);
  margin-bottom: 40px;
  display: block;
}

.pai-article-header__meta {
  display: flex;
  gap: 16px;
  align-items: center;
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.pai-article-header__category {
  font-family: var(--pai-font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--pai-accent);
}

.pai-article-header__date {
  font-family: var(--pai-font-mono);
  font-size: 0.75rem;
  color: var(--pai-text-muted);
}

.pai-article-header__author {
  font-family: var(--pai-font-mono);
  font-size: 0.75rem;
  color: var(--pai-text-muted);
}

.pai-article-header__title {
  font-family: var(--pai-font-serif);
  font-size: clamp(1.75rem, 3.5vw, 2.5rem);
  font-weight: 400;
  line-height: 1.2;
  color: var(--pai-text-primary);
  margin: 0 0 24px;
  max-width: var(--pai-prose-w);
}

.pai-article-body {
  max-width: var(--pai-prose-w);
  margin: 0 auto;
}

.pai-article-body h2 {
  font-size: 1.375rem;
  margin-top: 48px;
  margin-bottom: 16px;
  font-weight: 500;
  border-left: 3px solid var(--pai-accent-dim);
  padding-left: 16px;
}

.pai-article-body h3 {
  font-size: 1.125rem;
  margin-top: 32px;
  margin-bottom: 12px;
}

.pai-article-body p {
  font-size: 0.9375rem;
  line-height: 1.85;
  color: var(--pai-text-secondary);
  margin-bottom: 1.25em;
}

.pai-article-body ul, .pai-article-body ol {
  color: var(--pai-text-secondary);
  font-size: 0.9375rem;
  line-height: 1.8;
  padding-left: 1.5em;
  margin-bottom: 1.25em;
}

.pai-article-body blockquote {
  border-left: 3px solid var(--pai-accent-dim);
  padding-left: 20px;
  margin: 28px 0;
  color: var(--pai-text-secondary);
  font-style: italic;
}

.pai-article-body .pai-ref {
  font-size: 0.8125rem;
  color: var(--pai-text-muted);
  font-family: var(--pai-font-mono);
}

.pai-related-articles {
  background: var(--pai-bg-secondary);
  padding: 64px 0;
  border-top: 1px solid var(--pai-border);
}

.pai-related-articles__grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

@media (max-width: 700px) {
  .pai-related-articles__grid { grid-template-columns: 1fr; }
}

/* ─── Team Section ───────────────────────────────────────────────────── */
.pai-team-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.pai-team-card {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 16px;
}

.pai-team-card__avatar {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  overflow: hidden;
  flex-shrink: 0;
  background: var(--pai-bg-surface);
  border: 1px solid var(--pai-border);
}

.pai-team-card__avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.pai-team-card__avatar--letter {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  background: var(--pai-bg-surface);
  border: 1px solid var(--pai-border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--pai-font-serif);
  font-size: 1.5rem;
  font-weight: 500;
  color: var(--pai-accent-on-dark);
  flex-shrink: 0;
}

.pai-team-card__name {
  font-family: var(--pai-font-serif);
  font-size: 1.0625rem;
  font-weight: 500;
  color: var(--pai-text-primary);
  margin: 0;
}

.pai-team-card__title {
  font-family: var(--pai-font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--pai-text-muted);
  margin: 0;
}

.pai-team-card__bio {
  font-size: 0.875rem;
  line-height: 1.65;
  color: var(--pai-text-secondary);
  margin: 0;
}

@media (max-width: 700px) {
  .pai-team-grid { grid-template-columns: 1fr; }
}

/* ─── Contact / Form ─────────────────────────────────────────────────── */
.pai-form {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.pai-form__group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.pai-form__label {
  font-family: var(--pai-font-sans);
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--pai-text-secondary);
  letter-spacing: 0.04em;
}

.pai-form__input,
.pai-form__textarea {
  background: var(--pai-bg-surface);
  border: 1px solid var(--pai-border);
  border-radius: var(--pai-radius);
  color: var(--pai-text-primary);
  font-family: var(--pai-font-sans);
  font-size: 0.9375rem;
  padding: 12px 16px;
  width: 100%;
  transition: border-color 0.15s;
  outline: none;
}

.pai-form__input:focus,
.pai-form__textarea:focus {
  border-color: var(--pai-accent-dim);
}

.pai-form__input::placeholder,
.pai-form__textarea::placeholder {
  color: var(--pai-text-muted);
}

.pai-form__textarea {
  resize: vertical;
  min-height: 120px;
  line-height: 1.6;
}

.pai-contact-details {
  background: var(--pai-bg-surface);
  border: 1px solid var(--pai-border);
  border-radius: var(--pai-radius);
  padding: 28px 32px;
}

.pai-contact-details__heading {
  font-family: var(--pai-font-sans);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--pai-text-muted);
  margin: 0 0 20px;
}

.pai-contact-details__item {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  margin-bottom: 14px;
  font-size: 0.875rem;
  color: var(--pai-text-secondary);
}

.pai-contact-details__item i {
  color: var(--pai-accent);
  font-size: 0.875rem;
  width: 16px;
  flex-shrink: 0;
  margin-top: 2px;
}

.pai-contact-details__item a {
  color: var(--pai-accent-on-dark);
}

/* ─── Platform Feature List Panel ────────────────────────────────────── */
.pai-output-list {
  list-style: none;
  margin: 0 0 32px;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0;
}

.pai-output-list li {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  padding: 14px 0;
  border-bottom: 1px solid var(--pai-border);
  font-size: 0.9375rem;
  color: var(--pai-text-secondary);
  line-height: 1.6;
}

.pai-output-list li:last-child { border-bottom: none; }

.pai-output-list li i {
  color: var(--pai-accent);
  font-size: 0.875rem;
  flex-shrink: 0;
  margin-top: 3px;
}

/* ─── 404 Page ───────────────────────────────────────────────────────── */
.pai-404 {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 24px;
}

.pai-404__inner {
  max-width: 520px;
}

.pai-404__code {
  font-family: var(--pai-font-mono);
  font-size: clamp(5rem, 12vw, 8rem);
  font-weight: 400;
  color: var(--pai-text-muted);
  line-height: 1;
  margin: 0 0 24px;
  display: block;
}

.pai-404__heading {
  font-family: var(--pai-font-serif);
  font-size: 1.75rem;
  font-weight: 400;
  color: var(--pai-text-primary);
  margin: 0 0 16px;
}

.pai-404__body {
  font-size: 0.9375rem;
  color: var(--pai-text-secondary);
  margin: 0 0 40px;
}

/* ─── Use Case Sub-page ──────────────────────────────────────────────── */
.pai-uc-section {
  padding: 72px 0;
  border-bottom: 1px solid var(--pai-border);
}

.pai-uc-section:last-of-type { border-bottom: none; }

.pai-uc-section__heading {
  font-family: var(--pai-font-serif);
  font-size: clamp(1.25rem, 2.5vw, 1.75rem);
  font-weight: 500;
  color: var(--pai-text-primary);
  margin: 0 0 20px;
}

.pai-uc-section__body {
  max-width: var(--pai-prose-w);
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--pai-text-secondary);
}

.pai-uc-section__body p { margin: 0 0 1em; }
.pai-uc-section__body ul {
  padding-left: 1.5em;
  margin: 0 0 1em;
}
.pai-uc-section__body li { margin-bottom: 0.5em; }

/* ─── Methodology Page ───────────────────────────────────────────────── */
.pai-method-inner {
  max-width: var(--pai-content-w);
  margin: 0 auto;
  padding: 0 24px;
}

/* ─── Fade In Scroll ─────────────────────────────────────────────────── */
.fade-in {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.35s ease, transform 0.35s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: none;
}

/* ─── Utility ────────────────────────────────────────────────────────── */
.pai-divider {
  border: none;
  border-top: 1px solid var(--pai-border);
  margin: 0;
}

.pai-mono-label {
  font-family: var(--pai-font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--pai-text-muted);
}

.pai-text-accent { color: var(--pai-accent-on-dark); }

.pai-platform-img {
  width: 100%;
  height: auto;
  display: block;
  border-radius: var(--pai-radius);
  border: 1px solid var(--pai-border);
}

/* ─── Responsive ─────────────────────────────────────────────────────── */
@media (max-width: 600px) {
  :root {
    --pai-section-pad-v: 56px;
  }

  .pai-container { padding: 0 16px; }
  .pai-subhero { padding-top: 104px; }
  .pai-cta-band__inner { padding: 0 16px; }
  .pai-research-latest__header { flex-direction: column; align-items: flex-start; }
  .pai-pillars__grid,
  .pai-use-cases__grid,
  .pai-research-latest__grid { grid-template-columns: 1fr; }
  .pai-hero__actions { flex-direction: column; }
}

/* ─── Legal Pages (wrapper over template) ───────────────────────────── */
.pai-legal-wrap {
  background: var(--pai-bg-primary);
  padding-top: 64px;
}

.pai-legal-wrap .container {
  color: var(--pai-text-primary);
}

.pai-legal-wrap h1,
.pai-legal-wrap h2,
.pai-legal-wrap h3 {
  color: var(--pai-text-primary);
}

.pai-legal-wrap .meta {
  color: var(--pai-text-secondary);
  border-bottom-color: var(--pai-border);
}

.pai-legal-wrap h2 {
  border-left-color: var(--pai-accent);
}

.pai-legal-wrap table th {
  background: var(--pai-bg-surface);
  border-color: var(--pai-border);
}

.pai-legal-wrap table td {
  border-color: var(--pai-border);
}

.pai-legal-wrap tr:nth-child(even) td {
  background: var(--pai-bg-secondary);
}

.pai-legal-wrap .highlight-box {
  background: var(--pai-surface-hi);
  border-color: var(--pai-accent-dim);
}

.pai-legal-wrap .right-card {
  border-color: var(--pai-border);
  background: var(--pai-bg-surface);
}

.pai-legal-wrap .right-card h4 { color: var(--pai-accent-on-dark); }