/* ===== Custom properties ===== */
:root {
  color-scheme: light dark;

  --c-teal: #0d9488;
  --c-blue: #3b82f6;
  --c-amber: #d97706;
  --c-red: #dc2626;
  --c-green: #16a34a;

  --c-text: #1e293b;
  --c-text-muted: #64748b;
  --c-bg: #ffffff;
  --c-bg-alt: #f8fafc;
  --c-border: #e2e8f0;
  --c-header-bg: #0f172a;
  --c-hero-from: #0f172a;
  --c-hero-to: #134e4a;

  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --shadow-lg: 0 12px 30px rgba(0,0,0,0.12);

  --max-w: 1100px;
  --r: 8px;
  --r-lg: 12px;
  --tr: 0.2s ease;

  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  line-height: 1.5;
}

[data-theme="dark"] {
  --c-teal: #2dd4bf;
  --c-blue: #60a5fa;
  --c-amber: #fbbf24;
  --c-red: #f87171;
  --c-green: #4ade80;

  --c-text: #e2e8f0;
  --c-text-muted: #94a3b8;
  --c-bg: #0f172a;
  --c-bg-alt: #1e293b;
  --c-border: #334155;
  --c-hero-from: #020617;
  --c-hero-to: #042f2e;

  --shadow-sm: 0 1px 2px rgba(0,0,0,0.25);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.35);
  --shadow-lg: 0 12px 30px rgba(0,0,0,0.45);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --c-teal: #2dd4bf; --c-blue: #60a5fa; --c-amber: #fbbf24;
    --c-red: #f87171; --c-green: #4ade80;
    --c-text: #e2e8f0; --c-text-muted: #94a3b8;
    --c-bg: #0f172a; --c-bg-alt: #1e293b; --c-border: #334155;
    --c-hero-from: #020617; --c-hero-to: #042f2e;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.25);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.35);
    --shadow-lg: 0 12px 30px rgba(0,0,0,0.45);
  }
}

/* ===== Reset ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: 70px; }
body { background: var(--c-bg); color: var(--c-text); }
a { color: var(--c-teal); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; display: block; }

::selection { background: var(--c-teal); color: #ffffff; }
::-moz-selection { background: var(--c-teal); color: #ffffff; }

/* ===== Header ===== */
.site-header {
  position: sticky; top: 0; z-index: 100;
  display: flex; align-items: center; gap: 16px;
  padding: 0 24px; height: 56px;
  background: var(--c-header-bg); color: #e2e8f0;
  box-shadow: var(--shadow-md);
}
.site-logo {
  font-weight: 700; font-size: 1.1rem; color: #e2e8f0;
  white-space: nowrap;
}
.site-logo span { color: var(--c-teal); }
.site-logo:hover { text-decoration: none; }

.nav-links {
  list-style: none; display: flex; gap: 6px;
  margin-left: auto;
}
.nav-links a {
  color: #94a3b8; font-size: 0.85rem; padding: 6px 10px;
  border-radius: var(--r); transition: color var(--tr), background var(--tr);
}
.nav-links a:hover, .nav-links a.active {
  color: #e2e8f0; background: rgba(255,255,255,0.08); text-decoration: none;
}

.header-controls { display: flex; gap: 8px; margin-left: 12px; }
.theme-btn, .nav-btn {
  background: none; border: 1px solid rgba(255,255,255,0.15);
  color: #e2e8f0; border-radius: var(--r);
  width: 34px; height: 34px; font-size: 1.1rem; cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: border-color var(--tr);
}
.theme-btn:hover, .nav-btn:hover { border-color: rgba(255,255,255,0.35); }
.nav-btn { display: none; }

/* ===== Hero ===== */
.hero {
  background: linear-gradient(135deg, var(--c-hero-from) 0%, var(--c-hero-to) 100%);
  color: #e2e8f0; padding: 56px 24px 48px; text-align: center;
}
.hero h1 {
  font-size: clamp(1.4rem, 3vw, 2rem); max-width: 800px;
  margin: 0 auto 16px; line-height: 1.3;
}
.hero-sub {
  max-width: 680px; margin: 0 auto 32px; color: #94a3b8;
  font-size: 0.95rem; line-height: 1.6;
}
.stats-row {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px;
  max-width: var(--max-w); margin: 0 auto;
}
.hero-path {
  max-width: 860px;
  margin: 18px auto 0;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
}
.hero-step {
  padding: 7px 11px;
  border: 1px solid rgba(255,255,255,0.14);
  border-radius: 999px;
  background: rgba(255,255,255,0.06);
  color: #cbd5e1;
  font-size: 0.77rem;
  letter-spacing: 0.03em;
}
.stat-chip {
  background: rgba(255,255,255,0.06); border: 1px solid rgba(255,255,255,0.1);
  border-radius: var(--r-lg); padding: 16px 12px;
}
.stat-value {
  display: block; font-size: 1.6rem; font-weight: 700;
  font-family: 'SF Mono', 'Fira Code', 'Roboto Mono', Menlo, monospace;
  color: var(--c-teal);
}
.stat-label {
  display: block; font-size: 0.78rem; color: #94a3b8; margin-top: 4px;
}

/* ===== Content ===== */
.content {
  max-width: var(--max-w); margin: 0 auto;
  padding: 32px 24px 60px;
}
.section { margin-bottom: 48px; }
.section-header {
  display: flex; align-items: center; gap: 12px; margin-bottom: 16px;
}
.section-header h2 { font-size: 1.35rem; }
.section-tag {
  font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.08em;
  padding: 3px 8px; border-radius: 4px;
  background: var(--c-bg-alt); color: var(--c-text-muted);
  border: 1px solid var(--c-border);
}
.section > p {
  color: var(--c-text-muted); margin-bottom: 20px;
  max-width: 72ch; line-height: 1.6;
}

/* ===== Cards ===== */
.card {
  background: var(--c-bg-alt); border: 1px solid var(--c-border);
  border-radius: var(--r-lg); padding: 20px;
  box-shadow: var(--shadow-sm); transition: box-shadow var(--tr);
}
.card:hover { box-shadow: var(--shadow-md); }

/* ===== Charts ===== */
.chart-pair {
  display: grid; grid-template-columns: 1fr 1fr; gap: 16px;
  margin-bottom: 16px;
}
.chart-single { margin-bottom: 16px; }
.chart-container {
  background: var(--c-bg-alt); border: 1px solid var(--c-border);
  border-radius: var(--r-lg); padding: 16px;
  position: relative;
}
.chart-container canvas { width: 100% !important; }

/* ===== Insight / Warning boxes ===== */
.insight-box {
  border-left: 4px solid var(--c-teal);
  background: var(--c-bg-alt); border-radius: 0 var(--r) var(--r) 0;
  padding: 14px 16px; margin: 16px 0; font-size: 0.92rem;
  color: var(--c-text-muted); line-height: 1.55;
}
.insight-box strong { color: var(--c-text); }

.channel-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-bottom: 16px;
}
.channel-card {
  background: var(--c-bg-alt);
  border: 1px solid var(--c-border);
  border-radius: var(--r-lg);
  padding: 18px;
  box-shadow: var(--shadow-sm);
}
.channel-card h3 {
  font-size: 1rem;
  margin-bottom: 6px;
}
.channel-card p {
  color: var(--c-text-muted);
  font-size: 0.88rem;
  line-height: 1.55;
  margin-bottom: 14px;
}
.channel-metric {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding: 9px 0;
  border-top: 1px solid var(--c-border);
}
.channel-metric:first-of-type {
  border-top: none;
  padding-top: 0;
}
.channel-metric:last-of-type {
  padding-bottom: 0;
}
.channel-metric span {
  color: var(--c-text-muted);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.channel-metric strong {
  color: var(--c-text);
  font-size: 0.95rem;
  text-align: right;
}

/* ===== Tables ===== */
.table-wrap {
  overflow-x: auto; margin: 16px 0;
  border: 1px solid var(--c-border); border-radius: var(--r-lg);
}
.data-table {
  width: 100%; border-collapse: collapse; font-size: 0.85rem;
}
.data-table th {
  background: var(--c-bg-alt); color: var(--c-text-muted);
  font-weight: 600; text-transform: uppercase; letter-spacing: 0.04em;
  font-size: 0.75rem; padding: 10px 12px; text-align: left;
  border-bottom: 2px solid var(--c-border); white-space: nowrap;
}
.data-table td {
  padding: 8px 12px; border-bottom: 1px solid var(--c-border);
  font-family: 'SF Mono', 'Fira Code', 'Roboto Mono', Menlo, monospace;
  font-size: 0.8rem; white-space: nowrap;
}
.data-table tbody tr:hover { background: var(--c-bg-alt); }
.data-table tbody tr:last-child td { border-bottom: none; }

/* ===== Collapsible ===== */
.collapsible { margin: 16px 0; }
.collapsible-header {
  display: flex; align-items: center; gap: 8px;
  padding: 12px 16px; cursor: pointer;
  background: var(--c-bg-alt); border: 1px solid var(--c-border);
  border-radius: var(--r-lg); font-weight: 600; font-size: 0.95rem;
  color: var(--c-text); transition: background var(--tr);
}
.collapsible-header:hover { background: var(--c-border); }
.collapsible-header::before {
  content: '\25B6'; font-size: 0.7rem;
  transition: transform var(--tr); display: inline-block;
}
.collapsible.open .collapsible-header::before { transform: rotate(90deg); }
.collapsible-body {
  max-height: 0; overflow: hidden;
  transition: max-height 0.3s ease;
}
.collapsible.open .collapsible-body { max-height: 3000px; }

/* ===== Notes ===== */
.notes-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr;
  gap: 16px;
}
.note-card-title {
  font-size: 1rem;
  margin-bottom: 12px;
}
.note-list {
  display: grid;
  gap: 12px;
}
.note-item {
  padding: 12px 0;
  border-top: 1px solid var(--c-border);
}
.note-item:first-child {
  border-top: none;
  padding-top: 0;
}
.note-item strong,
.meta-block strong {
  display: block;
  margin-bottom: 4px;
  color: var(--c-text);
}
.note-item p,
.meta-block p,
.artifact-table td {
  color: var(--c-text-muted);
  line-height: 1.55;
}
.meta-block {
  margin-bottom: 16px;
}
.meta-block:last-child {
  margin-bottom: 0;
}
.provenance-card {
  margin-top: 16px;
}
.provenance-summary {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
  margin-bottom: 16px;
}
.provenance-chip {
  border: 1px solid var(--c-border);
  border-radius: var(--r);
  background: var(--c-bg);
  padding: 12px;
}
.provenance-chip strong {
  display: block;
  margin-bottom: 4px;
  color: var(--c-text);
  font-size: 1rem;
}
.provenance-chip span {
  color: var(--c-text-muted);
  font-size: 0.8rem;
}
.provenance-list {
  margin: 0 0 16px;
  padding-left: 18px;
  color: var(--c-text-muted);
}
.provenance-list li {
  margin-bottom: 6px;
}
.provenance-list li:last-child {
  margin-bottom: 0;
}
.artifact-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.8rem;
}
.artifact-table td {
  padding: 7px 0;
  border-top: 1px solid var(--c-border);
  vertical-align: top;
}
.artifact-table td:last-child {
  text-align: right;
  font-family: 'SF Mono', 'Fira Code', 'Roboto Mono', Menlo, monospace;
  color: var(--c-text);
}
.provenance-table td:last-child {
  text-align: left;
  font-family: inherit;
  color: var(--c-text-muted);
}

/* ===== Loading ===== */
.loading {
  text-align: center; padding: 40px; color: var(--c-text-muted);
  font-size: 0.9rem;
}

/* ===== Footer ===== */
.site-footer {
  text-align: center; padding: 32px 24px;
  color: var(--c-text-muted); font-size: 0.82rem;
  border-top: 1px solid var(--c-border);
}
.site-footer p { margin-bottom: 4px; }

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .nav-links { display: none; }
  .nav-links.open {
    display: flex; flex-direction: column;
    position: absolute; top: 56px; left: 0; right: 0;
    background: var(--c-header-bg); padding: 12px 24px;
    box-shadow: var(--shadow-lg); z-index: 99;
  }
  .nav-btn { display: flex; }
  .stats-row { grid-template-columns: 1fr 1fr; }
  .hero-path { justify-content: flex-start; }
  .chart-pair { grid-template-columns: 1fr; }
  .channel-grid { grid-template-columns: 1fr; }
  .notes-grid { grid-template-columns: 1fr; }
  .provenance-summary { grid-template-columns: 1fr 1fr; }
  .hero { padding: 40px 20px 36px; }
  .hero h1 { font-size: 1.3rem; }
  .content { padding: 24px 16px 48px; }
}

@media (max-width: 480px) {
  .stats-row { grid-template-columns: 1fr; }
  .stat-value { font-size: 1.3rem; }
  .provenance-summary { grid-template-columns: 1fr; }
}

@media print {
  .site-header, .site-footer, .theme-btn, .nav-btn { display: none; }
  .hero { background: #134e4a; -webkit-print-color-adjust: exact; }
}