/* ==========================================================================
   Design tokens
   ========================================================================== */
:root {
  --paper: #EDF1EA;
  --paper-alt: #E3E9DF;
  --line: #B9C7BC;
  --line-soft: #D2DCCC;
  --ink: #16241C;
  --ink-soft: #48564B;
  --ink-faint: #7C8B7D;
  --gold: #9C7A2E;
  --signal: #2F6F4E;

  --font-display: 'Newsreader', Georgia, serif;
  --font-body: 'IBM Plex Sans', -apple-system, sans-serif;
  --font-mono: 'IBM Plex Mono', 'Courier New', monospace;

  --sidebar-w: 240px;
  --content-max: 760px;
}

* { box-sizing: border-box; }

html { -webkit-font-smoothing: antialiased; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
}

a { color: var(--ink); }
a:focus-visible, button:focus-visible { outline: 2px solid var(--gold); outline-offset: 3px; }

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
}

/* ==========================================================================
   Layout shell: ledger index sidebar + content column
   ========================================================================== */
.shell {
  display: flex;
  min-height: 100vh;
}

.sidebar {
  width: var(--sidebar-w);
  flex-shrink: 0;
  border-right: 1px solid var(--line);
  padding: 2.5rem 1.75rem;
  position: sticky;
  top: 0;
  height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.sidebar-top .mark {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  color: var(--ink-faint);
  text-transform: uppercase;
  margin-bottom: 0.35rem;
}

.sidebar-top .name {
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 600;
  line-height: 1.25;
  margin-bottom: 1.75rem;
}

.ledger-nav { list-style: none; margin: 0; padding: 0; }
.ledger-nav li { border-top: 1px solid var(--line-soft); }
.ledger-nav li:last-child { border-bottom: 1px solid var(--line-soft); }
.ledger-nav a {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 0.5rem;
  padding: 0.62rem 0;
  text-decoration: none;
  font-size: 0.94rem;
  color: var(--ink-soft);
  transition: color 0.15s ease, padding-left 0.15s ease;
}
.ledger-nav a .ref {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--ink-faint);
}
.ledger-nav a:hover,
.ledger-nav a.active { color: var(--ink); padding-left: 4px; }
.ledger-nav a.active .ref { color: var(--gold); }

.sidebar-bottom {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--ink-faint);
  line-height: 1.7;
}
.sidebar-bottom a { color: var(--ink-faint); }
.sidebar-bottom a:hover { color: var(--gold); }

/* Mobile top bar */
.topbar { display: none; }

@media (max-width: 860px) {
  .shell { flex-direction: column; }
  .sidebar {
    position: relative;
    height: auto;
    width: 100%;
    border-right: none;
    border-bottom: 1px solid var(--line);
    padding: 1.25rem 1.5rem;
  }
  .sidebar-top .name { margin-bottom: 1rem; font-size: 1.15rem; }
  .ledger-nav { display: flex; flex-wrap: wrap; gap: 0 1rem; }
  .ledger-nav li { border: none; }
  .ledger-nav a { padding: 0.4rem 0; }
  .sidebar-bottom { margin-top: 1rem; }
}

main {
  flex: 1;
  min-width: 0;
  padding: 3.5rem 3rem 6rem;
}

.content-col { max-width: var(--content-max); }

@media (max-width: 600px) {
  main { padding: 2.25rem 1.25rem 4rem; }
}

/* ==========================================================================
   Type
   ========================================================================== */
.eyebrow {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--gold);
  margin: 0 0 0.9rem;
}

h1 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(2rem, 4vw, 2.9rem);
  line-height: 1.15;
  margin: 0 0 1rem;
  letter-spacing: -0.01em;
}

h2 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.55rem;
  margin: 2.75rem 0 1rem;
  letter-spacing: -0.005em;
}

h3 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.18rem;
  margin: 1.75rem 0 0.6rem;
}

p { margin: 0 0 1.1rem; color: var(--ink-soft); max-width: 66ch; }
p.lede { font-size: 1.1rem; color: var(--ink); max-width: 60ch; }

ul.plain, ol.plain { margin: 0 0 1.1rem; padding-left: 1.2rem; color: var(--ink-soft); }
ul.plain li, ol.plain li { margin-bottom: 0.4rem; }

code, .query {
  font-family: var(--font-mono);
  font-size: 0.88rem;
}

.query-line {
  font-family: var(--font-mono);
  font-size: 0.92rem;
  color: var(--signal);
  background: var(--paper-alt);
  border: 1px solid var(--line-soft);
  border-radius: 3px;
  padding: 0.85rem 1.1rem;
  display: inline-block;
  margin: 0.4rem 0 1.6rem;
  max-width: 100%;
  overflow-x: auto;
}

hr.rule { border: none; border-top: 1px solid var(--line); margin: 2.5rem 0; }

/* ==========================================================================
   Hero schema diagram
   ========================================================================== */
.schema-wrap { margin: 2.2rem 0 3rem; }
.schema-wrap svg { width: 100%; height: auto; display: block; }
.schema-caption {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--ink-faint);
  margin-top: 0.6rem;
}

/* ==========================================================================
   Highlight strip / metrics
   ========================================================================== */
.metric-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  margin: 2.5rem 0;
}
.metric {
  padding: 1.1rem 1.4rem 1.1rem 0;
  border-left: 1px solid var(--line-soft);
}
.metric:first-child { border-left: none; padding-left: 0; }
.metric .num {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  color: var(--signal);
  display: block;
  margin-bottom: 0.2rem;
}
.metric .label {
  font-size: 0.82rem;
  color: var(--ink-faint);
}

/* ==========================================================================
   Pillars / cards
   ========================================================================== */
.pillars {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem;
  margin: 2rem 0 3rem;
}
.pillar {
  border-top: 2px solid var(--ink);
  padding-top: 0.8rem;
}
.pillar h3 { margin-top: 0; }
.pillar p { font-size: 0.95rem; }

/* ==========================================================================
   Ledger list (blog index, project index)
   ========================================================================== */
.ledger-list { list-style: none; margin: 0; padding: 0; }
.ledger-item {
  border-top: 1px solid var(--line-soft);
  padding: 1.3rem 0;
  display: grid;
  grid-template-columns: 110px 1fr;
  gap: 1.25rem;
}
.ledger-list li:last-child { border-bottom: 1px solid var(--line-soft); }
.ledger-item .date {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--ink-faint);
  padding-top: 0.2rem;
}
.ledger-item h3 { margin: 0 0 0.35rem; font-size: 1.15rem; }
.ledger-item a { text-decoration: none; }
.ledger-item a:hover h3 { color: var(--gold); }
.ledger-item .excerpt { margin: 0; font-size: 0.95rem; }
.ledger-item .tag {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--signal);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

@media (max-width: 560px) {
  .ledger-item { grid-template-columns: 1fr; gap: 0.35rem; }
}

/* ==========================================================================
   Buttons / links
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  text-decoration: none;
  color: var(--ink);
  border: 1px solid var(--ink);
  padding: 0.65rem 1.1rem;
  border-radius: 3px;
  transition: background 0.15s ease, color 0.15s ease;
}
.btn:hover { background: var(--ink); color: var(--paper); }
.btn.ghost { border-color: var(--line); color: var(--ink-soft); }
.btn.ghost:hover { background: var(--ink-soft); border-color: var(--ink-soft); color: var(--paper); }

/* ==========================================================================
   Footer note inside content
   ========================================================================== */
.colophon {
  margin-top: 4rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--ink-faint);
}