/* ============================================
   BIT Index Tabula — Main Stylesheet
   A sophisticated, scholarly design system
   ============================================ */

:root {
  /* Color Palette */
  --color-bg: #fafafa;
  --color-bg-alt: #f4f4f4;
  --color-text: #1a1a1a;
  --color-text-secondary: #555;
  --color-text-muted: #888;
  --color-accent: #2a2a2a;
  --color-border: #e0e0e0;
  --color-border-light: #eee;
  
  /* Semantic Colors */
  --color-human: #2673e6;
  --color-ai: #28c88c;
  --color-symbiosis: #8c50dc;
  --color-invariant: #6b46c1;
  --color-framework: #2563eb;
  --color-history: #d97706;
  
  /* Status Colors */
  --color-complete: #059669;
  --color-progress: #d97706;
  --color-early: #dc2626;
  
  /* Typography */
  --font-serif: 'Crimson Pro', Georgia, serif;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  
  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;
  
  /* Layout */
  --max-width: 1200px;
  --content-width: 800px;
  
  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.3s ease;
  --transition-slow: 0.5s ease;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.06);
  --shadow-lg: 0 8px 30px rgba(0,0,0,0.08);
  --shadow-xl: 0 20px 50px rgba(0,0,0,0.1);
}

/* ============================================
   Reset & Base
   ============================================ */

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-serif);
  font-size: 1.125rem;
  line-height: 1.75;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ============================================
   Typography
   ============================================ */

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-sans);
  font-weight: 500;
  line-height: 1.3;
  letter-spacing: -0.02em;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 1.875rem; }
h3 { font-size: 1.375rem; }
h4 { font-size: 1.125rem; }

p {
  margin-bottom: var(--space-lg);
}

.lead {
  font-size: 1.25rem;
  line-height: 1.6;
  color: var(--color-text-secondary);
}

a {
  color: inherit;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition-fast);
}

a:hover {
  border-bottom-color: currentColor;
}

code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--color-bg-alt);
  padding: 0.15em 0.4em;
  border-radius: 3px;
}

/* ============================================
   Layout
   ============================================ */

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

.section {
  padding: var(--space-4xl) 0;
}

.section-header {
  margin-bottom: var(--space-2xl);
  text-align: center;
}

.section-marker {
  display: block;
  font-size: 1.5rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-md);
  opacity: 0.5;
}

.section-desc {
  color: var(--color-text-secondary);
  max-width: 600px;
  margin: var(--space-md) auto 0;
}

/* ============================================
   Source Library
   ============================================ */

.section-source .section-desc {
  max-width: 720px;
}

.source-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: var(--space-xl);
}

.source-card {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: var(--space-xl);
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.source-block {
  margin: var(--space-2xl) 0;
  border: 1px solid var(--color-border);
  border-radius: 12px;
  background: white;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.source-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  padding: var(--space-lg) var(--space-xl);
  border-bottom: 1px solid var(--color-border-light);
  background: var(--color-bg-alt);
}

.source-header h4 {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 1rem;
}

.source-actions {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.source-block pre {
  margin: 0;
  padding: var(--space-xl);
  background: #0f172a;
  color: #e2e8f0;
  overflow-x: auto;
  font-size: 0.875rem;
}

.source-block code {
  background: transparent;
  padding: 0;
  color: inherit;
  display: block;
  white-space: pre;
}

/* ============================================
   Navigation
   ============================================ */

.top-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(250, 250, 250, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border-light);
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-md) var(--space-xl);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-family: var(--font-mono);
  font-size: 0.9375rem;
  font-weight: 500;
  letter-spacing: -0.02em;
}

.circumpunct {
  font-size: 1.25rem;
  color: var(--color-symbiosis);
}

.nav-links {
  display: flex;
  gap: var(--space-xl);
}

.nav-link {
  font-family: var(--font-sans);
  font-size: 0.875rem;
  font-weight: 400;
  color: var(--color-text-secondary);
  border-bottom: none;
  padding: var(--space-xs) 0;
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--color-accent);
  transition: width var(--transition-normal);
}

.nav-link:hover {
  color: var(--color-text);
  border-bottom: none;
}

.nav-link:hover::after {
  width: 100%;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-sm);
}

.nav-toggle span {
  width: 20px;
  height: 2px;
  background: var(--color-text);
  border-radius: 1px;
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
  }
  
  .nav-toggle {
    display: flex;
  }
  
  .nav-links.active {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-bg);
    padding: var(--space-lg);
    border-bottom: 1px solid var(--color-border);
    gap: var(--space-md);
  }
}

/* ============================================
   Hero Section
   ============================================ */

.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  position: relative;
  padding: var(--space-4xl) var(--space-xl);
  text-align: center;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  z-index: -1;
}

.grid-overlay {
  position: absolute;
  inset: 0;
  background-image: 
    radial-gradient(circle at center, var(--color-border) 1px, transparent 1px);
  background-size: 40px 40px;
  opacity: 0.4;
}

.radial-gradient {
  position: absolute;
  inset: 0;
  background: radial-gradient(
    ellipse 80% 60% at 50% 40%,
    rgba(140, 80, 220, 0.03) 0%,
    transparent 70%
  );
}

.hero-symbol {
  margin-bottom: var(--space-2xl);
}

.symbiosis-visual {
  width: 180px;
  height: 180px;
  animation: float 6s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

.hero-title {
  font-size: 3.5rem;
  font-weight: 300;
  letter-spacing: -0.03em;
  margin-bottom: var(--space-md);
}

.hero-subtitle {
  font-family: var(--font-sans);
  font-size: 1.125rem;
  font-weight: 400;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-sm);
}

.hero-tagline {
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-2xl);
}

.hero-equation {
  font-family: var(--font-mono);
  font-size: 1rem;
  color: var(--color-symbiosis);
  padding: var(--space-md) var(--space-xl);
  background: rgba(140, 80, 220, 0.05);
  border: 1px solid rgba(140, 80, 220, 0.15);
  border-radius: 8px;
}

.scroll-indicator {
  position: absolute;
  bottom: var(--space-2xl);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
  color: var(--color-text-muted);
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.scroll-arrow {
  width: 20px;
  height: 20px;
  border-right: 2px solid currentColor;
  border-bottom: 2px solid currentColor;
  transform: rotate(45deg);
  animation: bounce 2s infinite;
}

@keyframes bounce {
  0%, 100% { transform: rotate(45deg) translateY(0); }
  50% { transform: rotate(45deg) translateY(5px); }
}

@media (max-width: 768px) {
  .hero-title {
    font-size: 2.25rem;
  }
  
  .symbiosis-visual {
    width: 140px;
    height: 140px;
  }
}

/* ============================================
   About Section
   ============================================ */

.section-about {
  background: var(--color-bg);
}

.about-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr;
  gap: var(--space-3xl);
  align-items: start;
}

.about-text .objectives {
  margin-top: var(--space-xl);
}

.about-text h3 {
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-md);
}

.about-text ol {
  list-style: none;
  counter-reset: objectives;
}

.about-text ol li {
  counter-increment: objectives;
  position: relative;
  padding-left: var(--space-xl);
  margin-bottom: var(--space-md);
}

.about-text ol li::before {
  content: counter(objectives) ".";
  position: absolute;
  left: 0;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--color-symbiosis);
}

.about-stats {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.stat-card {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: var(--space-lg);
  text-align: center;
  transition: box-shadow var(--transition-normal);
}

.stat-card:hover {
  box-shadow: var(--shadow-md);
}

.stat-number {
  display: block;
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 500;
  color: var(--color-symbiosis);
  line-height: 1.2;
}

.stat-label {
  display: block;
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-top: var(--space-xs);
}

@media (max-width: 768px) {
  .about-grid {
    grid-template-columns: 1fr;
  }
  
  .about-stats {
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: center;
  }
  
  .stat-card {
    flex: 1 1 140px;
    max-width: 180px;
  }
}

/* ============================================
   Research Section
   ============================================ */

.section-research {
  background: linear-gradient(180deg, var(--color-bg) 0%, var(--color-bg-alt) 100%);
}

.research-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: var(--space-xl);
}

.research-card {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: var(--space-xl);
  display: flex;
  flex-direction: column;
  transition: all var(--transition-normal);
}

.research-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

.research-card.featured {
  grid-column: span 2;
}

.research-card.invariant {
  border-color: rgba(107, 70, 193, 0.3);
  background: linear-gradient(135deg, white 0%, rgba(107, 70, 193, 0.02) 100%);
}

@media (max-width: 900px) {
  .research-card.featured {
    grid-column: span 1;
  }
  
  .research-grid {
    grid-template-columns: 1fr;
  }
}

.card-category {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-md);
}

.category-tag {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: var(--space-xs) var(--space-sm);
  border-radius: 4px;
  background: var(--color-bg-alt);
  color: var(--color-text-secondary);
}

.category-tag.history {
  background: rgba(217, 119, 6, 0.1);
  color: var(--color-history);
}

.category-tag.framework {
  background: rgba(37, 99, 235, 0.1);
  color: var(--color-framework);
}

.category-tag.invariant {
  background: rgba(107, 70, 193, 0.1);
  color: var(--color-invariant);
}

.status-badge {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 500;
  padding: var(--space-xs) var(--space-sm);
  border-radius: 10px;
}

.status-badge.complete {
  background: rgba(5, 150, 105, 0.1);
  color: var(--color-complete);
}

.status-badge.progress {
  background: rgba(217, 119, 6, 0.1);
  color: var(--color-progress);
}

.status-badge.early {
  background: rgba(220, 38, 38, 0.1);
  color: var(--color-early);
}

.card-content {
  flex: 1;
}

.card-title {
  font-size: 1.25rem;
  margin-bottom: var(--space-md);
  line-height: 1.4;
}

.card-abstract {
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-lg);
}

.card-equation {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  text-align: center;
  padding: var(--space-md);
  background: var(--color-bg-alt);
  border-radius: 6px;
  margin-bottom: var(--space-lg);
  color: var(--color-invariant);
}

.card-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-lg);
}

.meta-item strong {
  color: var(--color-text);
}

.card-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-top: auto;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  font-weight: 500;
  padding: var(--space-sm) var(--space-md);
  border-radius: 6px;
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
}

.btn-primary {
  background: var(--color-accent);
  color: white;
}

.btn-primary:hover {
  background: #1a1a1a;
  border-bottom: none;
}

.btn-secondary {
  background: var(--color-bg-alt);
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

.btn-secondary:hover {
  background: var(--color-border-light);
  border-bottom: none;
}

/* Card Layers (Four-Layer Cognition) */
.card-layers {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
  flex-wrap: wrap;
}

.layer {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: var(--space-xs) var(--space-sm);
  border-radius: 4px;
  font-weight: 500;
}

.layer.hyle { background: #e0f2fe; color: #0369a1; }
.layer.morphe { background: #fef3c7; color: #b45309; }
.layer.nous { background: #fce7f3; color: #be185d; }
.layer.telos { background: #d1fae5; color: #059669; }

.layer-arrow {
  color: var(--color-text-muted);
  font-size: 0.875rem;
}

/* Card Signals (Genotype-Phenotype) */
.card-signals {
  display: flex;
  justify-content: center;
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
  flex-wrap: wrap;
}

.signal {
  display: flex;
  flex-direction: column;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  padding: var(--space-sm);
  border-radius: 6px;
  min-width: 70px;
}

.signal span {
  font-size: 0.625rem;
  font-weight: 400;
  color: var(--color-text-muted);
  margin-top: 2px;
}

.signal.yaml { background: #dcfce7; color: #166534; }
.signal.xml { background: #fef3c7; color: #92400e; }
.signal.json { background: #dbeafe; color: #1e40af; }
.signal.md { background: #f3e8ff; color: #7c3aed; }

/* ============================================
   Domains Section
   ============================================ */

.section-domains {
  background: var(--color-bg);
}

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

.domain-card {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: var(--space-xl);
  text-align: center;
  transition: all var(--transition-normal);
}

.domain-card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--color-symbiosis);
}

.domain-icon {
  font-size: 1.75rem;
  color: var(--color-symbiosis);
  margin-bottom: var(--space-md);
  opacity: 0.8;
}

.domain-card h4 {
  font-size: 0.9375rem;
  margin-bottom: var(--space-sm);
}

.domain-card p {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  margin-bottom: 0;
  line-height: 1.6;
}

@media (max-width: 900px) {
  .domains-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 600px) {
  .domains-grid {
    grid-template-columns: 1fr;
  }
}

/* ============================================
   Submission Section
   ============================================ */

.section-submit {
  background: var(--color-bg-alt);
}

.submit-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3xl);
}

.submit-requirements h3,
.submit-flow h3 {
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-lg);
}

.submit-requirements ul {
  list-style: none;
}

.submit-requirements li {
  position: relative;
  padding-left: var(--space-lg);
  margin-bottom: var(--space-md);
  font-size: 0.9375rem;
}

.submit-requirements li::before {
  content: '→';
  position: absolute;
  left: 0;
  color: var(--color-symbiosis);
}

.submit-requirements a {
  color: var(--color-framework);
  border-bottom: 1px solid currentColor;
}

.flow-steps {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  flex-wrap: wrap;
  margin-bottom: var(--space-lg);
}

.flow-step {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  background: white;
  padding: var(--space-sm) var(--space-md);
  border: 1px solid var(--color-border);
  border-radius: 6px;
}

.step-num {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  color: white;
  background: var(--color-symbiosis);
  width: 20px;
  height: 20px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.step-text {
  font-family: var(--font-sans);
  font-size: 0.8125rem;
}

.flow-arrow {
  color: var(--color-text-muted);
  font-size: 1rem;
}

.flow-note {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  background: rgba(140, 80, 220, 0.05);
  padding: var(--space-sm) var(--space-md);
  border-radius: 4px;
  border-left: 3px solid var(--color-symbiosis);
}

@media (max-width: 768px) {
  .submit-content {
    grid-template-columns: 1fr;
  }
  
  .flow-steps {
    flex-direction: column;
    align-items: stretch;
  }
  
  .flow-arrow {
    transform: rotate(90deg);
    align-self: center;
  }
}

/* ============================================
   Footer
   ============================================ */

.site-footer {
  background: var(--color-accent);
  color: white;
  position: relative;
  overflow: hidden;
}

.footer-visualization {
  position: absolute;
  inset: 0;
  opacity: 0.1;
}

.footer-grid {
  width: 100%;
  height: 100%;
  background-image: 
    radial-gradient(circle at center, white 1px, transparent 1px);
  background-size: 30px 30px;
}

.footer-content {
  position: relative;
  z-index: 1;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-3xl) var(--space-xl);
  text-align: center;
}

.footer-brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  font-family: var(--font-mono);
  font-size: 1.125rem;
  margin-bottom: var(--space-lg);
}

.footer-brand .circumpunct {
  color: var(--color-symbiosis);
  filter: brightness(1.5);
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: var(--space-xl);
  margin-bottom: var(--space-lg);
}

.footer-links a {
  font-family: var(--font-sans);
  font-size: 0.875rem;
  color: rgba(255, 255, 255, 0.7);
  border-bottom: none;
  transition: color var(--transition-fast);
}

.footer-links a:hover {
  color: white;
  border-bottom: none;
}

.footer-equation {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--color-symbiosis);
  filter: brightness(1.4);
  margin-bottom: var(--space-lg);
}

.footer-tagline {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: rgba(255, 255, 255, 0.5);
  margin-bottom: 0;
}

/* ============================================
   Utilities
   ============================================ */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* ============================================
   Print Styles
   ============================================ */

@media print {
  .top-nav,
  .scroll-indicator,
  .footer-visualization {
    display: none;
  }
  
  .hero {
    min-height: auto;
    padding: var(--space-xl) 0;
  }
  
  .section {
    padding: var(--space-xl) 0;
  }
}