/* ── Theme tokens (mirrored from src/style.css) ───────────────── */

:root {
  --surface: #fafaf8;
  --surface-dim: #f0eeeb;
  --surface-container: #eaeae6;
  --surface-container-high: #e0deda;
  --on-surface: #1c1b1a;
  --on-surface-variant: #5c5955;
  --outline: #c4c0bb;
  --outline-variant: #e0dcda;
  --primary: #d97706;
  --primary-container: #fef3c7;
  --on-primary-container: #78350f;
  --code-bg: #f1f0ee;
  --shadow: rgba(0, 0, 0, 0.08);
  color-scheme: light;
}

.dark {
  --surface: #1a1a1a;
  --surface-dim: #121212;
  --surface-container: #242424;
  --surface-container-high: #2e2e2e;
  --on-surface: #e8e4e0;
  --on-surface-variant: #9e9892;
  --outline: #444040;
  --outline-variant: #2e2a2a;
  --primary: #f59e0b;
  --primary-container: #3d2800;
  --on-primary-container: #ffd980;
  --code-bg: #242424;
  --shadow: rgba(0, 0, 0, 0.5);
  color-scheme: dark;
}

/* ── Base ─────────────────────────────────────────────────────── */

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  background: var(--surface-dim);
  color: var(--on-surface);
  font-family: system-ui, -apple-system, sans-serif;
  line-height: 1.7;
  -webkit-text-size-adjust: 100%;
}

a {
  color: var(--primary);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

code {
  background: var(--code-bg);
  color: var(--on-surface);
  padding: 0.1em 0.35em;
  border-radius: 4px;
  font-size: 0.88em;
  font-family: "SF Mono", "Fira Code", ui-monospace, monospace;
}

/* ── Article (single column docs like attribution) ───────────── */

.article {
  max-width: 720px;
  margin: 0 auto;
  padding: 2.5rem 1.25rem 4rem;
}

.article h1 {
  font-family: Georgia, serif;
  color: var(--primary);
  font-size: 1.7rem;
  margin: 0.2rem 0 1.5rem;
}

.article h2 {
  font-size: 1.1rem;
  margin-top: 2.2rem;
  border-bottom: 1px solid var(--outline-variant);
  padding-bottom: 0.3rem;
}

.article .legal {
  font-size: 0.85rem;
  color: var(--on-surface-variant);
  margin-top: 0.3rem;
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  color: var(--on-surface-variant);
  font-size: 0.85rem;
  margin-bottom: 1.5rem;
}

.back-link:hover {
  color: var(--primary);
}

/* ── Layout (sidebar + content for how-it-works) ─────────────── */

.layout {
  display: flex;
  max-width: 1100px;
  margin: 0 auto;
  position: relative;
}

.sidebar {
  width: 220px;
  flex-shrink: 0;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  padding: 1.5rem 1rem 2rem 1.5rem;
  border-right: 1px solid var(--outline-variant);
  font-size: 0.82rem;
  background: var(--surface);
}

.sidebar a {
  display: block;
  padding: 0.32rem 0.55rem;
  border-radius: 6px;
  margin: 0.1rem 0;
  color: var(--on-surface-variant);
  font-weight: 500;
}

.sidebar a:hover,
.sidebar a.active {
  background: var(--primary-container);
  color: var(--on-primary-container);
  text-decoration: none;
}

.sidebar .brand {
  font-family: Georgia, serif;
  font-weight: 800;
  color: var(--primary);
  font-size: 1.05rem;
  margin-bottom: 1.2rem;
  display: block;
  padding: 0;
}

.sidebar .brand:hover {
  background: none;
}

.sidebar .section-label {
  font-size: 0.68rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--on-surface-variant);
  opacity: 0.7;
  margin: 1rem 0 0.3rem;
  padding-left: 0.55rem;
}

.content {
  flex: 1;
  min-width: 0;
  padding: 2rem 2.5rem 4rem;
  background: var(--surface-dim);
}

.content h1 {
  font-size: 1.8rem;
  font-family: Georgia, serif;
  color: var(--primary);
  margin: 0 0 0.5rem;
}

.content .subtitle {
  font-size: 1.05rem;
  color: var(--on-surface-variant);
  margin-bottom: 2.5rem;
}

.content h2 {
  font-size: 1.25rem;
  margin-top: 3rem;
  padding-bottom: 0.3rem;
  border-bottom: 2px solid var(--primary-container);
  color: var(--on-surface);
}

.content h3 {
  font-size: 1rem;
  margin-top: 1.8rem;
  color: var(--on-surface-variant);
}

.content p {
  margin: 0.8rem 0;
}

.content ul {
  padding-left: 1.4rem;
}

/* ── Diagrams (always light card so SVG colours stay legible) ── */

.diagram {
  margin: 1.5rem 0;
  text-align: center;
  background: #fafaf8;
  border: 1px solid #e5e3e0;
  border-radius: 10px;
  padding: 1.2rem 1rem 0.8rem;
  overflow-x: auto;
  color: #1c1b1a;
}

.diagram svg {
  max-width: 100%;
  height: auto;
}

.diagram figcaption,
.diagram .fig-caption,
/* biome-ignore lint/style/noDescendingSpecificity: standalone fig-caption also needs these styles */
  .fig-caption {
  font-size: 0.8rem;
  color: #64748b;
  margin-top: 0.4rem;
  text-align: center;
  font-style: italic;
}

/* ── Cards, callouts, formulas ───────────────────────────────── */

.stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
  gap: 0.8rem;
  margin: 1.5rem 0;
}

.stat {
  background: var(--surface);
  border: 1px solid var(--outline-variant);
  border-radius: 10px;
  padding: 0.9rem;
  text-align: center;
}

.stat .num {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--primary);
  font-family: Georgia, serif;
}

.stat .label {
  font-size: 0.72rem;
  color: var(--on-surface-variant);
  margin-top: 0.15rem;
}

.formula {
  background: var(--code-bg);
  color: var(--on-surface);
  padding: 0.8rem 1rem;
  border-radius: 8px;
  font-family: "SF Mono", "Fira Code", ui-monospace, monospace;
  font-size: 0.85rem;
  margin: 1rem 0;
  overflow-x: auto;
  line-height: 1.6;
}

.example {
  background: var(--surface);
  border-left: 3px solid var(--primary);
  padding: 0.8rem 1rem;
  margin: 1.2rem 0;
  font-size: 0.9rem;
  border-radius: 0 8px 8px 0;
}

.example strong {
  color: var(--primary);
}

.placeholder {
  background: var(--primary-container);
  color: var(--on-primary-container);
  border-radius: 8px;
  padding: 1.2rem;
  text-align: center;
  margin: 1.5rem 0;
  font-size: 0.85rem;
  font-style: italic;
}

.layers {
  margin: 1.2rem 0;
}

.layer {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  padding: 0.45rem 0;
  border-bottom: 1px solid var(--outline-variant);
}

.layer-num {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--primary);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.7rem;
  font-weight: 700;
  flex-shrink: 0;
}

.layer-label {
  font-weight: 600;
  font-size: 0.85rem;
  min-width: 100px;
  color: var(--on-surface);
}

.layer-desc {
  font-size: 0.8rem;
  color: var(--on-surface-variant);
}

.hist-bar {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin: 0.2rem 0;
  font-size: 0.8rem;
}

.hist-bar .bar {
  background: var(--primary);
  height: 16px;
  border-radius: 2px;
  min-width: 2px;
}

.hist-bar .label {
  width: 60px;
  text-align: right;
  color: var(--on-surface-variant);
  flex-shrink: 0;
  font-size: 0.75rem;
}

.hist-bar .count {
  color: var(--on-surface-variant);
  font-size: 0.7rem;
}

table {
  border-collapse: collapse;
  width: 100%;
  margin: 1rem 0;
  font-size: 0.85rem;
}

th,
td {
  padding: 0.5rem 0.65rem;
  text-align: left;
  border-bottom: 1px solid var(--outline-variant);
}

th {
  color: var(--on-surface-variant);
  font-weight: 600;
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.content footer {
  margin-top: 3rem;
  padding: 1.5rem 0;
  border-top: 1px solid var(--outline-variant);
  font-size: 0.78rem;
  color: var(--on-surface-variant);
  text-align: center;
}

/* ── Mobile sidebar drawer ────────────────────────────────────── */

.sidebar-toggle {
  display: none;
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 50;
  width: 42px;
  height: 42px;
  border-radius: 10px;
  border: 1px solid var(--outline-variant);
  background: var(--surface);
  color: var(--on-surface);
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: 0 2px 8px var(--shadow);
}

.sidebar-toggle svg {
  width: 22px;
  height: 22px;
}

.sidebar-backdrop {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
  z-index: 40;
}

.sidebar-backdrop.open {
  display: block;
}

@media (max-width: 768px) {
  .sidebar-toggle {
    display: inline-flex;
  }

  .sidebar {
    position: fixed;
    top: 0;
    left: 0;
    width: 260px;
    height: 100vh;
    z-index: 45;
    transform: translateX(-100%);
    transition: transform 220ms ease;
    border-right: 1px solid var(--outline-variant);
    box-shadow: 4px 0 16px var(--shadow);
    padding-top: 60px;
  }

  .sidebar.open {
    transform: translateX(0);
  }

  .content {
    padding: 4rem 1.1rem 3rem;
  }

  .layout {
    display: block;
  }
}