/* =========================================
   EXAONE 4.5 — Exaone Quantum Design System
   Primary: #d2bbff | Accent: #41eec2 | BG: #0f0b3c
   ========================================= */

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

:root {
  --primary: #d2bbff;
  --primary-container: #220053;
  --secondary: #41eec2;
  --secondary-container: #00d1a7;
  --background: #0f0b3c;
  --surface: #0f0b3c;
  --surface-low: #181445;
  --surface-container: #1c1949;
  --surface-high: #262454;
  --surface-highest: #312f5f;
  --on-surface: #e3dfff;
  --on-surface-variant: #c9c4d0;
  --outline-variant: rgba(72, 69, 79, 0.5);
  --tertiary: #cabff9;
  --tertiary-container: #1a1040;
  --font-serif: 'Noto Serif', Georgia, serif;
  --font-sans: 'Inter', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  --radius: 0.5rem;
  --shadow-glow: 0 20px 40px -10px rgba(34, 0, 83, 0.4);
}

html { scroll-behavior: smooth; }

body {
  background-color: var(--background);
  color: var(--on-surface);
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* ============ STICKY NAV ============ */
.sticky-nav {
  position: sticky;
  top: 0;
  z-index: 9999;
  background: rgba(15, 11, 60, 0.9);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  padding: 10px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid rgba(210, 187, 255, 0.08);
}

.nav-back {
  color: var(--secondary);
  text-decoration: none;
  font-size: 0.875rem;
  font-family: var(--font-sans);
  font-weight: 500;
  transition: opacity 0.2s;
}
.nav-back:hover { opacity: 0.75; }

.nav-arxiv-btn {
  background: linear-gradient(90deg, var(--secondary-container), var(--secondary));
  color: #00382b;
  padding: 6px 14px;
  border-radius: var(--radius);
  font-size: 0.8rem;
  font-weight: 600;
  text-decoration: none;
  transition: opacity 0.2s;
}
.nav-arxiv-btn:hover { opacity: 0.85; }

/* ============ HERO ============ */
.hero {
  position: relative;
  min-height: 90vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  background: linear-gradient(135deg, #1a1040 0%, #0f0b3c 45%, #220053 100%);
}

.hero-bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  opacity: 0.15;
  filter: blur(2px);
  z-index: 0;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: rgba(15, 11, 60, 0.55);
  z-index: 1;
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 820px;
  margin: 0 auto;
  padding: 80px 32px;
  text-align: center;
}

.hero-badge {
  display: inline-block;
  background: rgba(65, 238, 194, 0.15);
  color: var(--secondary);
  border: 1px solid rgba(65, 238, 194, 0.3);
  border-radius: 100px;
  padding: 4px 14px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 20px;
}

.hero-title {
  font-family: var(--font-serif);
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--on-surface);
  margin-bottom: 16px;
  line-height: 1.15;
}

.hero-subtitle {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  color: var(--primary);
  margin-bottom: 24px;
  font-style: italic;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: center;
  margin-bottom: 24px;
}

.meta-chip {
  background: var(--surface-highest);
  color: var(--on-surface-variant);
  padding: 5px 12px;
  border-radius: 100px;
  font-size: 0.8rem;
  display: flex;
  align-items: center;
  gap: 5px;
}

.meta-icon { font-size: 0.85rem; }

.hero-abstract {
  color: var(--on-surface-variant);
  font-size: 1rem;
  line-height: 1.7;
  max-width: 680px;
  margin: 0 auto 32px;
}

.hero-actions {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 28px;
}

.btn {
  display: inline-block;
  padding: 12px 24px;
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
  transition: opacity 0.2s, transform 0.2s;
  cursor: pointer;
}
.btn:hover { opacity: 0.85; transform: translateY(-1px); }

.btn-primary {
  background: linear-gradient(90deg, var(--secondary-container), var(--secondary));
  color: #00382b;
}

.btn-glass {
  background: rgba(49, 47, 95, 0.6);
  backdrop-filter: blur(8px);
  color: var(--primary);
  border: 1px solid rgba(210, 187, 255, 0.15);
}

.hero-actions .btn { /* in hero context */ }

.capability-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
}

.cap-badge {
  background: rgba(26, 16, 64, 0.8);
  border: 1px solid rgba(202, 191, 249, 0.2);
  color: var(--tertiary);
  padding: 6px 14px;
  border-radius: 100px;
  font-size: 0.82rem;
  font-weight: 500;
}

/* ============ CONTENT SECTIONS ============ */
.content-section {
  padding: 80px 32px;
}

.alt-bg {
  background: var(--surface-low);
}

.section-container {
  max-width: 900px;
  margin: 0 auto;
}

.section-heading {
  font-family: var(--font-serif);
  font-size: 1.85rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 32px;
  letter-spacing: -0.01em;
}

.subsection-heading {
  font-family: var(--font-serif);
  font-size: 1.3rem;
  font-weight: 600;
  color: var(--tertiary);
  margin: 40px 0 16px;
}

.glass-card {
  background: rgba(49, 47, 95, 0.4);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1px solid rgba(210, 187, 255, 0.1);
  border-radius: var(--radius);
  padding: 32px;
  margin-bottom: 24px;
  box-shadow: var(--shadow-glow);
}

.glass-card p + p {
  margin-top: 16px;
}

.glass-card p {
  color: var(--on-surface-variant);
  line-height: 1.7;
}

/* ============ STATS ROW ============ */
.stats-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-top: 24px;
}

.stat-card {
  background: var(--surface-container);
  border-radius: var(--radius);
  padding: 28px 20px;
  text-align: center;
  box-shadow: var(--shadow-glow);
}

.stat-value {
  font-family: var(--font-serif);
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--secondary);
  margin-bottom: 6px;
}

.stat-label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--on-surface-variant);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

/* ============ PAPER FIGURES ============ */
.paper-figure {
  margin: 32px 0;
  text-align: center;
}

.paper-img {
  max-width: 100%;
  border-radius: var(--radius);
  border: 1px solid rgba(210, 187, 255, 0.08);
}

.paper-img-medium {
  max-width: 600px;
}

figcaption {
  margin-top: 12px;
  font-size: 0.85rem;
  color: var(--on-surface-variant);
  font-style: italic;
  line-height: 1.5;
}

/* ============ METHOD CARDS ============ */
.method-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
  margin-top: 24px;
}

.method-card {
  background: var(--surface-container);
  border-radius: var(--radius);
  padding: 24px;
  border-left: 3px solid var(--secondary);
}

.method-title {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--secondary);
  margin-bottom: 12px;
  letter-spacing: 0.02em;
}

.method-card p {
  font-size: 0.9rem;
  color: var(--on-surface-variant);
  line-height: 1.6;
}

/* ============ HIGHLIGHT CARDS ============ */
.highlights-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin: 24px 0;
}

.highlight-card {
  background: linear-gradient(135deg, var(--primary-container), var(--surface-container));
  border-radius: var(--radius);
  padding: 24px 20px;
  text-align: center;
  box-shadow: var(--shadow-glow);
}

.highlight-metric {
  font-family: var(--font-serif);
  font-size: 2.8rem;
  font-weight: 700;
  color: var(--secondary);
  margin-bottom: 8px;
}

.highlight-label {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--on-surface-variant);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* ============ DEPLOYMENT LINKS ============ */
.deploy-links {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin-top: 24px;
}

.deploy-btn {
  display: inline-block;
  background: rgba(49, 47, 95, 0.6);
  border: 1px solid rgba(65, 238, 194, 0.25);
  color: var(--secondary);
  padding: 14px 24px;
  border-radius: var(--radius);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.9rem;
  backdrop-filter: blur(8px);
  transition: all 0.2s;
}
.deploy-btn:hover {
  background: rgba(65, 238, 194, 0.12);
  transform: translateY(-2px);
}

/* ============ CONCLUSION CONTRIB CARDS ============ */
.contrib-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
  margin-top: 28px;
}

.contrib-card {
  background: rgba(49, 47, 95, 0.4);
  border-radius: var(--radius);
  padding: 24px;
  border-top: 2px solid var(--primary);
}

.contrib-title {
  font-family: var(--font-serif);
  font-size: 1rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 10px;
}

.contrib-card p {
  font-size: 0.88rem;
  color: var(--on-surface-variant);
  line-height: 1.6;
}

/* ============ FOOTER ============ */
.paper-footer {
  background: var(--tertiary-container);
  padding: 24px 32px;
  text-align: center;
  font-size: 0.82rem;
  color: var(--on-surface-variant);
  line-height: 1.6;
}

.paper-footer a {
  color: var(--secondary);
  text-decoration: none;
}
.paper-footer a:hover { text-decoration: underline; }

/* ============ FLECTO EXPLANATION UI CLASSES ============ */
.flecto-note,
.flecto-callout,
.flecto-card,
.flecto-panel {
  margin: 24px 0;
  border-radius: var(--radius);
  font-size: 0.9rem;
  color: var(--on-surface-variant);
  line-height: 1.6;
}

.flecto-note::before,
.flecto-callout::before,
.flecto-card::before,
.flecto-panel::before {
  content: "🤖 AI explanation";
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  color: #60a5fa;
  letter-spacing: 0.06em;
  display: block;
  margin-bottom: 0.5em;
}

.flecto-note {
  background: rgba(28, 25, 73, 0.6);
  border-left: 3px solid #60a5fa;
  padding: 14px 16px;
}

.flecto-callout {
  background: rgba(34, 0, 83, 0.4);
  border: 1px solid rgba(96, 165, 250, 0.2);
  padding: 20px 24px;
}

.flecto-card {
  background: var(--surface-container);
  box-shadow: var(--shadow-glow);
  border: 1px solid rgba(210, 187, 255, 0.1);
  padding: 24px;
}

.flecto-panel {
  background: rgba(26, 16, 64, 0.6);
  border: 1px solid rgba(202, 191, 249, 0.15);
  padding: 28px;
}

.flecto-card h4,
.flecto-panel h4 {
  font-family: var(--font-serif);
  font-size: 1rem;
  color: var(--primary);
  margin-bottom: 10px;
}

/* ============ REVEAL ANIMATION ============ */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  .reveal {
    opacity: 1 !important;
    transform: none !important;
    transition: none !important;
  }
}

/* ============ RESPONSIVE ============ */
@media (max-width: 640px) {
  .stats-row,
  .highlights-row {
    grid-template-columns: 1fr;
  }
  .hero-content { padding: 60px 20px; }
  .content-section { padding: 60px 20px; }
  .method-cards,
  .contrib-cards { grid-template-columns: 1fr; }
}