/* ========== DESIGN TOKENS ========== */
:root {
  --bg: #0D1117;
  --bg-card: #161B22;
  --bg-card-hover: #1C2333;
  --fg: #E6EDF3;
  --fg-muted: #8B949E;
  --fg-dim: #484F58;
  --accent: #58A6FF;
  --accent-dim: #1F6FEB;
  --green: #3FB950;
  --green-dim: rgba(63,185,80,0.15);
  --red: #F85149;
  --red-dim: rgba(248,81,73,0.15);
  --yellow: #D29922;
  --yellow-dim: rgba(210,153,34,0.15);
  --purple: #BC8CFF;
  --purple-dim: rgba(188,140,255,0.15);
  --border: #30363D;
  --border-accent: #58A6FF;
  --font: 'Outfit', 'Segoe UI', system-ui, sans-serif;
  --radius: 12px;
  --radius-sm: 8px;
}

/* ========== RESET ========== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--fg);
  font-size: 16px;
  line-height: 1.6;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ========== LAYOUT ========== */
.container { max-width: 1100px; margin: 0 auto; padding: 0 20px; }

/* ========== NAV ========== */
.nav {
  background: rgba(13,17,23,0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}
.nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 56px;
}
.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}
.nav-icon {
  font-size: 22px;
}
.nav-title {
  font-size: 17px;
  font-weight: 700;
  color: var(--fg);
  letter-spacing: 0.02em;
}
.nav-links {
  display: flex;
  gap: 4px;
  list-style: none;
}
.nav-links a {
  display: block;
  padding: 6px 14px;
  font-weight: 500;
  font-size: 14px;
  color: var(--fg-muted);
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: all 0.15s;
}
.nav-links a:hover {
  color: var(--fg);
  background: var(--bg-card);
}
.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 4px 10px;
  color: var(--fg-muted);
  cursor: pointer;
  font-size: 18px;
}
@media (max-width: 640px) {
  .nav-toggle { display: block; }
  .nav-links {
    display: none;
    position: absolute;
    top: 56px;
    left: 0; right: 0;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 8px;
  }
  .nav-links.open { display: flex; }
}

/* ========== HERO ========== */
.hero {
  padding: 80px 20px 60px;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  top: -120px;
  left: 50%;
  transform: translateX(-50%);
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(88,166,255,0.08) 0%, transparent 70%);
  pointer-events: none;
}
.hero-label {
  display: inline-block;
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--accent);
  padding: 4px 12px;
  border: 1px solid var(--accent-dim);
  border-radius: 20px;
  margin-bottom: 24px;
}
.hero h1 {
  font-size: 56px;
  font-weight: 900;
  line-height: 1;
  letter-spacing: -0.03em;
  margin-bottom: 16px;
}
.hero h1 .accent { color: var(--accent); }
.hero-desc {
  font-size: 18px;
  color: var(--fg-muted);
  max-width: 520px;
  margin: 0 auto 36px;
  line-height: 1.7;
}
.hero-stats {
  display: flex;
  justify-content: center;
  gap: 40px;
  flex-wrap: wrap;
}
.hero-stat {
  text-align: center;
}
.hero-stat-value {
  font-size: 28px;
  font-weight: 900;
  color: var(--fg);
}
.hero-stat-label {
  font-size: 12px;
  color: var(--fg-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}
@media (max-width: 640px) {
  .hero { padding: 48px 20px 40px; }
  .hero h1 { font-size: 36px; }
  .hero-desc { font-size: 16px; }
}

/* ========== SECTIONS ========== */
.section {
  padding: 72px 0;
  border-top: 1px solid var(--border);
}
.section-tag {
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent);
  margin-bottom: 8px;
}
.section-title {
  font-size: 32px;
  font-weight: 900;
  line-height: 1.1;
  margin-bottom: 8px;
}
.section-desc {
  font-size: 15px;
  color: var(--fg-muted);
  max-width: 560px;
  margin-bottom: 32px;
}

/* ========== CARDS ========== */
.card-grid {
  display: grid;
  gap: 16px;
}
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
@media (max-width: 768px) {
  .grid-2, .grid-3 { grid-template-columns: 1fr; }
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: all 0.2s;
  text-decoration: none;
  color: inherit;
  display: block;
}
.card:hover {
  border-color: var(--border-accent);
  background: var(--bg-card-hover);
  text-decoration: none;
  transform: translateY(-2px);
}

.card-featured {
  grid-column: span 2;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}
@media (max-width: 768px) {
  .card-featured { grid-column: span 1; grid-template-columns: 1fr; }
}

/* ========== TAGS ========== */
.tag {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 2px 8px;
  border-radius: 4px;
  margin-bottom: 10px;
}
.tag-sector { background: var(--purple-dim); color: var(--purple); }
.tag-asset { background: var(--green-dim); color: var(--green); }
.tag-framework { background: var(--yellow-dim); color: var(--yellow); }
.tag-insight { background: var(--red-dim); color: var(--red); }
.tag-hypothesis { background: rgba(88,166,255,0.15); color: var(--accent); }

.card-title {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 6px;
  line-height: 1.3;
}
.card-desc {
  font-size: 14px;
  color: var(--fg-muted);
  line-height: 1.6;
}
.card-meta {
  margin-top: 12px;
  font-size: 12px;
  color: var(--fg-dim);
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}
.card-rating {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  font-weight: 700;
  margin-top: 8px;
}
.rating-badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 12px;
  font-weight: 700;
}
.rating-low { background: var(--red-dim); color: var(--red); }
.rating-mid { background: var(--yellow-dim); color: var(--yellow); }
.rating-high { background: var(--green-dim); color: var(--green); }

/* ========== FORMULA BOX ========== */
.formula-box {
  background: rgba(88,166,255,0.06);
  border: 1px solid rgba(88,166,255,0.15);
  border-radius: var(--radius-sm);
  padding: 16px 20px;
  font-family: 'SF Mono', 'Fira Code', monospace;
  font-size: 13px;
  line-height: 2;
  color: var(--fg-muted);
}
.formula-box .hl { color: var(--accent); font-weight: 700; }

/* ========== HYPOTHESIS TABLE ========== */
.hyp-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}
.hyp-table th {
  text-align: left;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--fg-muted);
  padding: 8px 12px;
  border-bottom: 1px solid var(--border);
}
.hyp-table td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}
.hyp-table tr:last-child td { border-bottom: none; }
.hyp-id {
  font-family: 'SF Mono', monospace;
  font-size: 12px;
  color: var(--accent);
  font-weight: 700;
}
.status-open {
  display: inline-block;
  padding: 1px 6px;
  font-size: 11px;
  font-weight: 700;
  border-radius: 4px;
  background: var(--yellow-dim);
  color: var(--yellow);
}

/* ========== THREE LAYER ========== */
.layer-flow {
  display: flex;
  align-items: center;
  gap: 0;
  margin: 24px 0;
  flex-wrap: wrap;
}
.layer-box {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 16px 20px;
  flex: 1;
  min-width: 200px;
}
.layer-box h4 {
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 6px;
}
.layer-box p {
  font-size: 13px;
  color: var(--fg-muted);
  line-height: 1.5;
}
.layer-arrow {
  font-size: 20px;
  color: var(--fg-dim);
  padding: 0 12px;
  flex-shrink: 0;
}
.l1 h4 { color: var(--green); }
.l2 h4 { color: var(--yellow); }
.l3 h4 { color: var(--accent); }
@media (max-width: 640px) {
  .layer-arrow { transform: rotate(90deg); padding: 8px 0; }
  .layer-flow { flex-direction: column; align-items: stretch; }
}

/* ========== FOOTER ========== */
.footer {
  border-top: 1px solid var(--border);
  padding: 32px 20px;
}
.footer-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.footer-text {
  font-size: 13px;
  color: var(--fg-dim);
}
.footer-links {
  display: flex;
  gap: 20px;
  list-style: none;
}
.footer-links a {
  font-size: 13px;
  color: var(--fg-muted);
  text-decoration: none;
}
.footer-links a:hover { color: var(--accent); }
@media (max-width: 640px) {
  .footer-inner { flex-direction: column; gap: 12px; text-align: center; }
}

/* ========== SECTION: METHODOLOGY CARDS ========== */
.method-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 12px;
}
.method-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 20px;
  transition: border-color 0.2s;
}
.method-card:hover { border-color: var(--fg-dim); }
.method-icon { font-size: 24px; margin-bottom: 10px; }
.method-card h4 {
  font-size: 14px;
  font-weight: 700;
  margin-bottom: 4px;
}
.method-card p {
  font-size: 13px;
  color: var(--fg-muted);
  line-height: 1.5;
}