/* ═══════════════════════════════════════════
   AIOS — Dark theme AI Operating System page
   Hero · Problem Stats · Three Tiers ·
   Industry Library · CTA · Footer
   ═══════════════════════════════════════════ */

/* ═══════════════════════════════════════════
   AIOS HERO
   ═══════════════════════════════════════════ */
.aios-hero {
  padding: 140px 0 80px;
  position: relative;
}
.aios-hero::after {
  content: '';
  position: absolute;
  top: 80px;
  left: 50%;
  transform: translateX(-50%);
  width: 600px;
  height: 400px;
  background: radial-gradient(ellipse, rgba(217,119,87,0.04) 0%, transparent 70%);
  pointer-events: none;
}
.aios-hero-label {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 24px;
  display: flex;
  align-items: center;
  gap: 16px;
}
.aios-hero-label::after {
  content: '';
  flex: 1;
  height: 1px;
  background: linear-gradient(90deg, rgba(217,119,87,0.4), transparent 60%);
  max-width: 120px;
}
.aios-hero-title {
  font-family: var(--font-ui);
  font-size: clamp(40px, 6vw, 72px);
  font-weight: 300;
  line-height: 1.1;
  letter-spacing: -0.03em;
  color: var(--white);
  margin-bottom: 28px;
  max-width: 800px;
  text-align: center;
  margin-left: auto;
  margin-right: auto;
}
.aios-hero-sub {
  font-size: 20px;
  font-weight: 400;
  line-height: 1.65;
  color: var(--body);
  max-width: 620px;
  text-align: center;
  margin-left: auto;
  margin-right: auto;
}

/* ═══════════════════════════════════════════
   PROBLEM — Stats strip
   ═══════════════════════════════════════════ */
.aios-problem {
  padding: 40px 0 24px;
}
.problem-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-bottom: 48px;
}
.problem-stat {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 32px 28px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  position: relative;
  overflow: hidden;
}
.problem-stat::before {
  content: '';
  position: absolute;
  top: -1px;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(217,119,87,0.35), transparent);
}
.problem-num {
  font-family: var(--font-ui);
  font-size: 42px;
  font-weight: 600;
  line-height: 1;
  color: var(--accent);
}
.problem-label {
  font-size: 14px;
  font-weight: 500;
  color: var(--muted);
  line-height: 1.5;
}
.problem-body {
  font-size: 18px;
  font-weight: 400;
  line-height: 1.75;
  color: var(--body);
  max-width: 740px;
  text-align: center;
  margin-left: auto;
  margin-right: auto;
}

/* ═══════════════════════════════════════════
   THREE-TIER ARCHITECTURE
   ═══════════════════════════════════════════ */
.aios-tiers {
  padding: 24px 0 100px;
  position: relative;
}
.tiers-title {
  font-family: var(--font-ui);
  font-size: clamp(32px, 4.5vw, 48px);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.025em;
  color: var(--white);
  margin-bottom: 16px;
}
/* ── Layer diagram (image) ── */
.layer-diagram {
  margin: 0 auto 24px;
  max-width: 420px;
}
.layer-diagram-img {
  width: 100%;
  height: auto;
  display: block;
}

.tiers-intro {
  font-size: 17px;
  font-weight: 400;
  line-height: 1.75;
  color: var(--body);
  max-width: 600px;
  margin: 0 auto 56px;
  text-align: center;
}

/* ── Individual tier card ── */
.tier {
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 48px 44px;
  margin-bottom: 16px;
  position: relative;
  overflow: hidden;
  transition: border-color 0.3s ease;
}
.tier:hover { border-color: var(--border-hover); }

/* Tier-specific left accent bar */
.tier::before {
  content: '';
  position: absolute;
  top: 24px;
  bottom: 24px;
  left: 0;
  width: 3px;
  border-radius: 0 3px 3px 0;
}
.tier-3 { background: var(--surface); }
.tier-3::before { background: var(--accent); }
.tier-2 { background: var(--off); }
.tier-2::before { background: rgba(255,255,255,0.3); }
.tier-1 { background: var(--surface); }
.tier-1::before { background: var(--muted); }

.tier-header {
  display: flex;
  align-items: baseline;
  gap: 16px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}
.tier-num {
  font-family: var(--font-ui);
  font-size: 13px;
  font-weight: 600;
  color: var(--accent);
  opacity: 0.7;
}
.tier-name {
  font-family: var(--font-ui);
  font-size: 24px;
  font-weight: 700;
  color: var(--white);
  letter-spacing: -0.02em;
}
.tier-tag {
  font-family: var(--font-ui);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
  margin-left: auto;
}
.tier-body {
  font-size: 16px;
  font-weight: 400;
  line-height: 1.75;
  color: var(--body);
  max-width: 720px;
  margin-bottom: 24px;
}

/* Capability pills */
.tier-capabilities {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.tier-capabilities span {
  font-family: var(--font-ui);
  font-size: 12px;
  font-weight: 500;
  color: var(--body);
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--border);
  border-radius: 100px;
  padding: 6px 16px;
  white-space: nowrap;
  transition: border-color 0.2s ease, color 0.2s ease;
}
.tier-capabilities span:hover {
  border-color: var(--border-hover);
  color: var(--white);
}

/* Accent pills for tier-3 */
.tier-3 .tier-capabilities span {
  border-color: rgba(217,119,87,0.15);
  background: rgba(217,119,87,0.05);
}
.tier-3 .tier-capabilities span:hover {
  border-color: rgba(217,119,87,0.3);
}

/* ═══════════════════════════════════════════
   INDUSTRY LIBRARY
   ═══════════════════════════════════════════ */
.aios-library {
  padding: 80px 0 100px;
  position: relative;
}
.aios-library::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--border-hover), transparent);
}
.library-title {
  font-family: var(--font-ui);
  font-size: clamp(28px, 4vw, 40px);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.025em;
  color: var(--white);
  margin-bottom: 16px;
  max-width: 600px;
  text-align: center;
  margin-left: auto;
  margin-right: auto;
}
.library-intro {
  font-size: 17px;
  font-weight: 400;
  line-height: 1.75;
  color: var(--body);
  max-width: 640px;
  margin: 0 auto 48px;
  text-align: center;
}

.library-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
.library-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 36px 32px;
  display: flex;
  flex-direction: column;
  transition: background 0.35s ease, border-color 0.35s ease, box-shadow 0.35s ease, transform 0.35s var(--ease);
}
.library-card:hover {
  background: var(--surface-hover);
  border-color: var(--border-hover);
  box-shadow: 0 8px 40px rgba(255,255,255,0.02), 0 0 0 1px rgba(255,255,255,0.06);
  transform: translateY(-2px);
}
.library-icon {
  color: var(--accent);
  margin-bottom: 20px;
  opacity: 0.8;
}
.library-card-title {
  font-family: var(--font-ui);
  font-size: 18px;
  font-weight: 700;
  color: var(--white);
  margin-bottom: 12px;
}
.library-card-body {
  font-size: 14px;
  font-weight: 400;
  line-height: 1.7;
  color: var(--muted);
  margin-bottom: 20px;
}

/* Locked CTA button */
.library-locked {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-top: auto;
  font-family: var(--font-ui);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--accent);
  text-decoration: none;
  border: 1px solid rgba(217,119,87,0.3);
  border-radius: 100px;
  padding: 8px 18px;
  transition: background 0.3s ease, border-color 0.3s ease, color 0.3s ease;
}
.library-locked svg {
  flex-shrink: 0;
}
.library-locked:hover {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--black);
}
.library-locked:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}
.library-locked:active {
  opacity: 0.85;
}

/* ═══════════════════════════════════════════
   CTA
   ═══════════════════════════════════════════ */
.aios-cta {
  padding: 40px 0 100px;
}
.cta-frame {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 24px;
  padding: 72px 56px;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.cta-frame::before {
  content: '';
  position: absolute;
  top: -1px;
  left: 50%;
  transform: translateX(-50%);
  width: 140px;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(217,119,87,0.4), transparent);
}
.cta-title {
  font-family: var(--font-ui);
  font-size: clamp(28px, 4vw, 40px);
  font-weight: 700;
  line-height: 1.25;
  color: var(--white);
  margin-bottom: 20px;
}
.cta-body {
  font-size: 16px;
  font-weight: 400;
  line-height: 1.75;
  color: var(--body);
  max-width: 520px;
  margin: 0 auto 36px;
}
.cta-btn {
  display: inline-flex;
  align-items: center;
  font-family: var(--font-ui);
  font-size: 15px;
  font-weight: 600;
  color: var(--white);
  text-decoration: none;
  border: 1.5px solid var(--accent);
  border-radius: 100px;
  padding: 14px 36px;
  transition: background 0.3s ease, color 0.3s ease;
}
.cta-btn:hover {
  background: var(--accent);
  color: var(--black);
}

/* ═══════════════════════════════════════════
   FOOTER — same as index
   ═══════════════════════════════════════════ */
.footer {
  padding: 48px var(--page-pad);
  border-top: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: relative;
}
.footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: var(--page-pad);
  right: var(--page-pad);
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--border-hover), transparent);
}
.footer-left {
  font-size: 13px;
  font-weight: 400;
  color: var(--muted);
}
.footer-right a {
  font-size: 13px;
  font-weight: 500;
  color: var(--body);
  text-decoration: none;
  transition: color 0.2s ease;
}
.footer-right a:hover { color: var(--white); }

/* ═══════════════════════════════════════════
   RESPONSIVE
   ═══════════════════════════════════════════ */
@media (max-width: 900px) {
  .aios-hero { padding: 120px 0 60px; }
  .problem-grid { grid-template-columns: 1fr; }
  .library-grid { grid-template-columns: 1fr 1fr; }
  .tier { padding: 36px 32px; }
  .tier-header { flex-direction: column; gap: 8px; }
  .tier-tag { margin-left: 0; }
  .cta-frame { padding: 56px 36px; }
}
@media (max-width: 480px) {
  .aios-hero { padding: 100px 0 48px; }
  .aios-hero-title { font-size: 36px; }
  .aios-hero-sub { font-size: 17px; }
  .problem-num { font-size: 32px; }
  .problem-stat { padding: 24px 20px; }
  .problem-body { font-size: 16px; }
  .aios-tiers { padding: 16px 0 72px; }
  .tiers-title { font-size: 28px; }
  .tier { padding: 28px 20px; }
  .tier-name { font-size: 20px; }
  .tier-capabilities span { font-size: 11px; padding: 5px 12px; }
  .library-grid { grid-template-columns: 1fr; }
  .library-title { font-size: 24px; }
  .aios-library { padding: 56px 0 72px; }
  .aios-cta { padding: 24px 0 60px; }
  .cta-frame { padding: 40px 24px; }
  .footer { flex-direction: column; gap: 12px; text-align: center; }
}