/* ── Reset & base ─────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #fafafa;
  --fg: #1a1a1a;
  --muted: #5a5a5a;
  --accent: #0b5cff;
  --accent-dim: #0840a8;
  --border: #e0e0e0;
  --card-bg: #ffffff;
  --mono: "SF Mono", "Fira Code", "Cascadia Code", Consolas, monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --serif: "Iowan Old Style", "Palatino Linotype", "Times New Roman", serif;
  --max-w: 780px;
}

html { font-size: 17px; scroll-behavior: smooth; }

body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--fg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

/* ── Layout ───────────────────────────────────────────────── */
.wrap {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ── Hero ─────────────────────────────────────────────────── */
.hero {
  padding: 5rem 0 3rem;
  border-bottom: 1px solid var(--border);
}

.hero h1 {
  font-size: 2.6rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 0.6rem;
}

.hero .subtitle {
  font-size: 1.15rem;
  color: var(--muted);
  font-weight: 400;
  max-width: 560px;
  line-height: 1.55;
}

.hero .tagline {
  margin-top: 1.8rem;
  font-size: 1.05rem;
  font-family: var(--serif);
  font-style: italic;
  color: var(--muted);
  border-left: 3px solid var(--accent);
  padding-left: 1rem;
  max-width: 600px;
}

/* ── Sections ─────────────────────────────────────────────── */
section { padding: 3rem 0; }

section h2 {
  font-size: 1.35rem;
  font-weight: 600;
  margin-bottom: 1.2rem;
  letter-spacing: -0.01em;
}

section p { margin-bottom: 1rem; }

/* ── Reasoning chain ──────────────────────────────────────── */
.reasoning-chain {
  font-family: var(--mono);
  font-size: 0.92rem;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 1.2rem 1.5rem;
  margin: 1.5rem 0;
  line-height: 1.8;
  word-wrap: break-word;
}

/* ── Grounded list ────────────────────────────────────────── */
.grounded-list {
  list-style: none;
  padding: 0;
  margin: 1.2rem 0;
}

.grounded-list li {
  padding: 0.45rem 0 0.45rem 1.4rem;
  position: relative;
  font-size: 0.95rem;
}

.grounded-list li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: #1a9a3a;
  font-weight: 600;
}

.grounded-list li em {
  color: #c44;
  font-style: normal;
  font-weight: 500;
}

.grounded-list li em::before {
  content: "✗ ";
  color: #c44;
}

/* ── Architecture grid ────────────────────────────────────── */
.architecture-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin: 1.5rem 0;
}

.arch-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 1.3rem 1.4rem;
}

.arch-card h3 {
  font-size: 0.92rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--accent);
  margin-bottom: 0.5rem;
}

.arch-card p {
  font-size: 0.92rem;
  color: var(--muted);
  line-height: 1.55;
}

/* ── Learning loop ────────────────────────────────────────── */
.learning-loop {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 0;
  margin: 2rem 0 0.5rem;
  padding: 1rem;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 6px;
}

.loop-step {
  font-family: var(--mono);
  font-size: 0.82rem;
  font-weight: 700;
  padding: 0.4rem 0.7rem;
  background: #f0f4ff;
  border-radius: 4px;
  color: var(--accent);
}

.loop-arrow {
  color: var(--muted);
  font-size: 0.9rem;
  padding: 0 0.2rem;
}

/* ── Principle box ────────────────────────────────────────── */
.principle {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 1.5rem 1.8rem;
  margin: 1.5rem 0;
  font-family: var(--serif);
  font-size: 1.1rem;
  line-height: 1.5;
}

/* ── Lineage cards ────────────────────────────────────────── */
.lineage-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.2rem;
  margin: 1.5rem 0;
}

.lineage-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 1.4rem 1.6rem;
}

.lineage-card h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.lineage-card p {
  font-size: 0.92rem;
  color: var(--muted);
  line-height: 1.55;
  margin-bottom: 0.5rem;
}

.lineage-card a {
  color: var(--accent);
  text-decoration: none;
}

.lineage-card a:hover { text-decoration: underline; }

.lineage-card .ref {
  font-size: 0.82rem;
  font-family: var(--mono);
  color: var(--muted);
}

/* ── Disclaimer ───────────────────────────────────────────── */
.disclaimer {
  font-size: 0.85rem;
  color: var(--muted);
  font-style: italic;
  margin-top: 1.5rem;
}

/* ── Contributions list ───────────────────────────────────── */
.contrib-list {
  list-style: none;
  padding: 0;
}

.contrib-list li {
  padding: 0.4rem 0 0.4rem 1.2rem;
  position: relative;
  font-size: 0.95rem;
}

.contrib-list li::before {
  content: "→";
  position: absolute;
  left: 0;
  color: var(--accent);
}

/* ── Footer ───────────────────────────────────────────────── */
footer {
  padding: 2rem 0;
  border-top: 1px solid var(--border);
  font-size: 0.82rem;
  color: var(--muted);
  text-align: center;
}

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

/* ── Links ────────────────────────────────────────────────── */
a { color: var(--accent); }

/* ── Responsive ───────────────────────────────────────────── */
@media (max-width: 600px) {
  .hero { padding: 3rem 0 2rem; }
  .hero h1 { font-size: 2rem; }
  section { padding: 2rem 0; }
  .architecture-grid { grid-template-columns: 1fr; }
  .learning-loop { font-size: 0.78rem; }
}