/* Statinfer Institute of AI & Data Science — Custom Homepage Design System
   Matches tenant custom homepage rules: Sticky header, no nesting, uses platform CSS tokens, clean responsive bento UI */

:root {
  --font-sans: var(--font-doc-space-grotesk, 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif);
  --font-body: var(--font-doc-inter, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif);

  --st-bg: #070913;
  --st-bg-surface: #0e1222;
  --st-bg-surface-elevated: #141930;
  --st-border: rgba(255, 255, 255, 0.08);
  --st-border-focus: rgba(99, 102, 241, 0.5);

  --st-primary: var(--primary, #4f46e5);
  --st-primary-glow: rgba(79, 70, 229, 0.25);
  --st-accent: var(--accent, #06b6d4);
  --st-accent-glow: rgba(6, 182, 212, 0.2);
  --st-gold: #f59e0b;

  --st-text-main: #f8fafc;
  --st-text-muted: #94a3b8;
  --st-text-subtle: #64748b;

  --st-radius-sm: 8px;
  --st-radius-md: 14px;
  --st-radius-lg: 20px;
  --st-radius-xl: 28px;

  --sign-in-w: var(--sign-in-corner-width, 8.5rem);
  --sign-in-h: var(--sign-in-corner-height, 4.25rem);
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-family: var(--font-body);
  background-color: var(--st-bg);
  color: var(--st-text-main);
  line-height: 1.6;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
}

body {
  min-height: 100vh;
  overflow-x: hidden;
  background-color: var(--st-bg);
  background-image:
    radial-gradient(ellipse 70% 50% at 50% -10%, rgba(79, 70, 229, 0.18), transparent 70%),
    radial-gradient(ellipse 50% 40% at 85% 30%, rgba(6, 182, 212, 0.12), transparent 60%);
  background-repeat: no-repeat;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color 0.2s ease, opacity 0.2s ease;
}

/* ================= CONTAINER & TYPOGRAPHY ================= */
.st-container {
  width: 100%;
  max-width: 1240px;
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

.st-section {
  padding-top: 5.5rem;
  padding-bottom: 5.5rem;
  position: relative;
}

.st-section-lead {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 3.5rem auto;
}

.st-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 0.9rem;
  border-radius: 9999px;
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  background: rgba(99, 102, 241, 0.12);
  border: 1px solid rgba(99, 102, 241, 0.28);
  color: #a5b4fc;
  margin-bottom: 1.25rem;
}

.st-pill-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--st-accent);
  box-shadow: 0 0 10px var(--st-accent);
}

.st-heading-xl {
  font-family: var(--font-sans);
  font-size: clamp(2.4rem, 5vw, 4rem);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.03em;
  color: var(--st-text-main);
  margin-bottom: 1.25rem;
}

.st-heading-lg {
  font-family: var(--font-sans);
  font-size: clamp(1.85rem, 3.5vw, 2.75rem);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--st-text-main);
  margin-bottom: 1rem;
}

.st-heading-md {
  font-family: var(--font-sans);
  font-size: 1.35rem;
  font-weight: 700;
  line-height: 1.3;
  color: var(--st-text-main);
  margin-bottom: 0.5rem;
}

.st-text-gradient {
  background: linear-gradient(135deg, #ffffff 30%, #93c5fd 65%, #a78bfa 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.st-subtext {
  font-size: clamp(1.05rem, 2vw, 1.2rem);
  color: var(--st-text-muted);
  line-height: 1.6;
}

/* ================= HEADER & NAV ================= */
.st-header {
  position: relative;
  z-index: 50;
  border-bottom: 1px solid var(--st-border);
  background: rgba(7, 9, 19, 0.85);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}

.st-header-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--sign-in-h);
  padding-right: var(--sign-in-w); /* Platform safe-zone */
}

.st-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.st-logo-img {
  height: 38px;
  width: auto;
  max-width: 175px;
  display: block;
}

.st-nav-links {
  display: flex;
  align-items: center;
  gap: 1.75rem;
}

.st-nav-links a {
  font-size: 0.925rem;
  font-weight: 500;
  color: var(--st-text-muted);
}

.st-nav-links a:hover {
  color: var(--st-text-main);
}

/* Mobile navigation drawer (native details/summary, no JavaScript) */
.st-mobile-nav {
  display: none;
}

.st-mobile-summary {
  list-style: none;
  cursor: pointer;
  padding: 0.5rem;
  color: var(--st-text-muted);
  font-size: 1.5rem;
  user-select: none;
}

.st-mobile-summary::-webkit-details-marker {
  display: none;
}

.st-mobile-menu {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background: var(--st-bg-surface-elevated);
  border-bottom: 1px solid var(--st-border);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.7);
}

.st-mobile-menu a {
  font-size: 1rem;
  font-weight: 600;
  color: var(--st-text-main);
}

.st-mobile-signin-btn {
  display: inline-block;
  padding: 0.75rem 1rem;
  background: var(--st-primary);
  color: #ffffff;
  border-radius: var(--st-radius-sm);
  text-align: center;
}

/* ================= BUTTONS ================= */
.st-btn-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1rem;
}

.st-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.85rem 1.75rem;
  font-size: 0.975rem;
  font-weight: 600;
  border-radius: var(--st-radius-md);
  transition: all 0.25s ease;
  cursor: pointer;
}

.st-btn-primary {
  background: linear-gradient(135deg, #4f46e5 0%, #3b82f6 100%);
  color: #ffffff;
  box-shadow: 0 4px 18px var(--st-primary-glow);
  border: 1px solid rgba(255, 255, 255, 0.15);
}

.st-btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px var(--st-primary-glow);
  color: #ffffff;
}

.st-btn-secondary {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--st-border);
  color: var(--st-text-main);
}

.st-btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(255, 255, 255, 0.2);
  transform: translateY(-2px);
}

/* ================= HERO SECTION ================= */
.st-hero {
  padding-top: 5rem;
  padding-bottom: 4rem;
  position: relative;
}

.st-hero-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 3.5rem;
  align-items: center;
}

.st-hero-left {
  max-width: 680px;
}

.st-hero-badges-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 2rem;
}

.st-micro-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.35rem 0.75rem;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--st-border);
  border-radius: var(--st-radius-sm);
  font-size: 0.8125rem;
  color: var(--st-text-muted);
}

/* Bento Hero Quick Card */
.st-hero-card {
  background: var(--st-bg-surface);
  border: 1px solid var(--st-border);
  border-radius: var(--st-radius-xl);
  padding: 2.25rem;
  position: relative;
  overflow: hidden;
  box-shadow: 0 25px 60px rgba(0, 0, 0, 0.45);
}

.st-hero-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--st-primary), var(--st-accent), var(--st-gold));
}

.st-card-tag {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--st-accent);
  margin-bottom: 0.75rem;
}

.st-hero-metric-box {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
  margin-top: 1.75rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--st-border);
}

.st-mini-metric strong {
  display: block;
  font-family: var(--font-sans);
  font-size: 1.75rem;
  font-weight: 800;
  color: #ffffff;
}

.st-mini-metric span {
  font-size: 0.8125rem;
  color: var(--st-text-muted);
}

/* ================= STATS TICKER STRIP ================= */
.st-stats-strip {
  background: var(--st-bg-surface);
  border-top: 1px solid var(--st-border);
  border-bottom: 1px solid var(--st-border);
  padding: 2.5rem 0;
}

.st-stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 2rem;
}

.st-stat-item {
  text-align: center;
  position: relative;
}

.st-stat-item:not(:last-child)::after {
  content: "";
  position: absolute;
  right: -1rem;
  top: 20%;
  height: 60%;
  width: 1px;
  background: var(--st-border);
}

.st-stat-num {
  font-family: var(--font-sans);
  font-size: clamp(2rem, 3.5vw, 2.75rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: #ffffff;
  line-height: 1.1;
}

.st-stat-num b {
  color: var(--st-accent);
  font-weight: 800;
}

.st-stat-lbl {
  font-size: 0.875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--st-text-muted);
  margin-top: 0.35rem;
}

/* ================= BENTO PROGRAM TRACKS ================= */
.st-bento-grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: 1.5rem;
}

.st-bento-card {
  background: var(--st-bg-surface);
  border: 1px solid var(--st-border);
  border-radius: var(--st-radius-lg);
  padding: 2rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
  overflow: hidden;
  transition: transform 0.25s ease, border-color 0.25s ease;
}

.st-bento-card:hover {
  transform: translateY(-4px);
  border-color: rgba(99, 102, 241, 0.4);
}

.st-bento-card-8 {
  grid-column: span 8;
}

.st-bento-card-4 {
  grid-column: span 4;
}

.st-bento-card-6 {
  grid-column: span 6;
}

.st-bento-card-12 {
  grid-column: span 12;
}

.st-bento-header {
  margin-bottom: 1.25rem;
}

.st-track-code {
  font-family: monospace;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--st-accent);
  background: rgba(6, 182, 212, 0.1);
  padding: 0.2rem 0.5rem;
  border-radius: var(--st-radius-sm);
  display: inline-block;
  margin-bottom: 0.75rem;
}

.st-chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-top: 1.25rem;
  margin-bottom: 1.5rem;
}

.st-chip {
  font-size: 0.78rem;
  padding: 0.25rem 0.65rem;
  border-radius: 9999px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.08);
  color: var(--st-text-muted);
}

.st-bento-link {
  font-size: 0.9rem;
  font-weight: 600;
  color: #818cf8;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  margin-top: auto;
}

.st-bento-link:hover {
  color: #a5b4fc;
}

/* ================= CLIENT LOGO CLOUD & TABLE ================= */
.st-clients-cloud {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 1rem 1.75rem;
  margin-bottom: 3rem;
}

.st-client-badge {
  padding: 0.6rem 1.25rem;
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--st-border);
  border-radius: var(--st-radius-sm);
  font-size: 0.95rem;
  font-weight: 600;
  color: #cbd5e1;
  letter-spacing: 0.01em;
}

.st-table-container {
  background: var(--st-bg-surface);
  border: 1px solid var(--st-border);
  border-radius: var(--st-radius-lg);
  overflow: hidden;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
}

.st-table-wrap {
  width: 100%;
  overflow-x: auto;
}

.st-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.925rem;
}

.st-table th {
  background: rgba(255, 255, 255, 0.03);
  padding: 1rem 1.5rem;
  font-size: 0.8125rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--st-text-muted);
  border-bottom: 1px solid var(--st-border);
}

.st-table td {
  padding: 1.1rem 1.5rem;
  border-bottom: 1px solid var(--st-border);
  color: #e2e8f0;
}

.st-table tr:last-child td {
  border-bottom: none;
}

.st-table tr:hover td {
  background: rgba(255, 255, 255, 0.02);
}

.st-table .num-cell {
  font-family: var(--font-sans);
  font-weight: 700;
  color: var(--st-accent);
}

/* ================= YOUTUBE VIDEO GRID ================= */
.st-yt-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
}

.st-yt-card {
  background: var(--st-bg-surface);
  border: 1px solid var(--st-border);
  border-radius: var(--st-radius-md);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: transform 0.25s ease, border-color 0.25s ease;
}

.st-yt-card:hover {
  transform: translateY(-4px);
  border-color: rgba(239, 68, 68, 0.4);
}

.st-yt-badge {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  color: #ef4444;
  margin-bottom: 0.5rem;
}

.st-yt-card p {
  font-size: 0.85rem;
  color: var(--st-text-muted);
  margin-bottom: 1.25rem;
  line-height: 1.5;
}

.st-yt-cta {
  font-size: 0.85rem;
  font-weight: 600;
  color: #f87171;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  margin-top: auto;
}

/* ================= METHODOLOGY GRID ================= */
.st-method-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.75rem;
}

.st-method-card {
  background: var(--st-bg-surface);
  border: 1px solid var(--st-border);
  border-radius: var(--st-radius-lg);
  padding: 2.25rem;
  position: relative;
}

.st-method-step {
  font-family: var(--font-sans);
  font-size: 2.5rem;
  font-weight: 800;
  color: rgba(255, 255, 255, 0.08);
  line-height: 1;
  margin-bottom: 1rem;
}

/* ================= CTA BANNER ================= */
.st-cta-box {
  background: linear-gradient(135deg, rgba(79, 70, 229, 0.2) 0%, rgba(6, 182, 212, 0.15) 100%);
  border: 1px solid rgba(99, 102, 241, 0.35);
  border-radius: var(--st-radius-xl);
  padding: 4rem 2.5rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}

/* ================= FOOTER ================= */
.st-footer {
  border-top: 1px solid var(--st-border);
  background: #04060d;
  padding: 4.5rem 0 2.5rem 0;
  color: var(--st-text-subtle);
  font-size: 0.875rem;
}

.st-footer-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: 2.5rem;
  margin-bottom: 3.5rem;
}

.st-footer-col h4 {
  font-family: var(--font-sans);
  color: var(--st-text-main);
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 1.25rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.st-footer-col ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.st-footer-col a {
  color: var(--st-text-muted);
}

.st-footer-col a:hover {
  color: var(--st-text-main);
}

.st-footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1.5rem;
  padding-top: 2rem;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
}

.st-footer-signin-link {
  color: #a5b4fc;
  font-weight: 600;
  padding: 0.4rem 0.9rem;
  border: 1px solid rgba(99, 102, 241, 0.3);
  border-radius: var(--st-radius-sm);
  background: rgba(99, 102, 241, 0.1);
}

.st-footer-signin-link:hover {
  background: rgba(99, 102, 241, 0.2);
  color: #ffffff;
}

/* ================= RESPONSIVE QUERIES ================= */
@media (max-width: 1024px) {
  .st-hero-grid {
    grid-template-columns: 1fr;
    gap: 2.5rem;
  }
  .st-bento-card-8, .st-bento-card-4, .st-bento-card-6 {
    grid-column: span 12;
  }
  .st-stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .st-stat-item:nth-child(2)::after {
    display: none;
  }
  .st-yt-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .st-footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .st-nav-links {
    display: none;
  }
  .st-mobile-nav {
    display: block;
  }
  .st-method-grid {
    grid-template-columns: 1fr;
  }
  .st-stats-grid {
    grid-template-columns: 1fr;
  }
  .st-stat-item::after {
    display: none;
  }
  .st-yt-grid {
    grid-template-columns: 1fr;
  }
  .st-footer-grid {
    grid-template-columns: 1fr;
  }
}