@import url('https://fonts.googleapis.com/css2?family=ET+Serif+Display:ital,wght@0,400;0,700;1,400&family=JetBrains+Mono:wght@400;500&family=Source+Serif+Pro:ital,wght@0,400;0,600;1,400&display=swap');

:root {
  --ink: #1a1a1a;
  --soft: #555;
  --rule: #d0d0d0;
  --accent: #c8102e;
  --paper: #fdfdfb;
  --highlight: #fff8b8;
}
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
body {
  font-family: 'Source Serif Pro', Georgia, serif;
  background: var(--paper);
  color: var(--ink);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.page {
  max-width: 760px;
  margin: 0 auto;
  padding: 48px 56px 96px;
}

/* ─── Header ─── */
header.title {
  border-bottom: 1px solid var(--ink);
  padding-bottom: 20px;
  margin-bottom: 40px;
}
header.title .eyebrow {
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 12px;
}
header.title h1 {
  font-family: 'ET Serif Display', Georgia, serif;
  font-size: 36px;
  font-weight: 700;
  letter-spacing: -0.015em;
  line-height: 1.05;
  margin-bottom: 8px;
}
header.title h1 .subtitle {
  font-weight: 400;
  color: var(--soft);
  font-style: italic;
  display: block;
  font-size: 20px;
  margin-top: 4px;
}
header.title .meta {
  font-family: 'JetBrains Mono', monospace;
  font-size: 10px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--soft);
  margin-top: 14px;
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
}
header.title .meta .tags { color: var(--accent); }

/* Visual grammar legend */
.legend {
  margin: 20px 0 0;
  padding: 12px 16px;
  background: rgba(0,0,0,0.02);
  border: 1px solid var(--rule);
  display: flex;
  flex-wrap: wrap;
  gap: 12px 20px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
}
.legend .swatch { display: inline-flex; align-items: center; gap: 7px; }
.legend .dot { width: 11px; height: 11px; border-radius: 50%; display: inline-block; }
.legend .dot.dashed { background: transparent; border: 1.4px dashed var(--soft); }
.legend .swatch b { font-weight: 500; color: var(--ink); }
.legend .label {
  font-size: 9px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--soft);
  margin-right: 2px;
}

/* ─── Sections ─── */
section {
  margin-bottom: 40px;
  padding-bottom: 32px;
  border-bottom: 1px solid var(--rule);
}
section:last-of-type { border-bottom: none; margin-bottom: 24px; }

.chno {
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 10px;
}
h2 {
  font-family: 'ET Serif Display', Georgia, serif;
  font-size: 24px;
  font-weight: 700;
  margin: 0 0 16px;
  line-height: 1.15;
}
p { margin-bottom: 16px; }
p:last-child { margin-bottom: 0; }
strong { font-weight: 600; }
em { font-style: italic; }
code {
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px;
  background: rgba(200, 16, 46, 0.06);
  padding: 1px 4px;
}

/* Inline cross-reference */
.xref {
  color: var(--accent);
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px;
  text-decoration: none;
  border-bottom: 1px solid var(--accent);
}

/* Inline diagram */
.diagram {
  margin: 20px 0;
  padding: 14px 0;
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
}
.diagram svg, .diagram img {
  display: block;
  width: 100%;
  max-width: 600px;
  margin: 0 auto;
}
.diagram .caption {
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  color: var(--soft);
  margin-top: 8px;
  text-align: center;
}

/* Formula + "reading it" */
.formula {
  margin: 20px 0 0;
  padding: 10px 18px 6px;
  background: rgba(0,0,0,0.025);
  border: 1px solid var(--rule);
  border-left: 2px solid var(--ink);
  overflow-x: auto;
  text-align: center;
}
.formula .lab {
  font-family: 'JetBrains Mono', monospace;
  font-size: 10px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--soft);
  display: block;
  margin-bottom: 4px;
  text-align: left;
}
.formula .eq {
  font-family: 'ET Serif Display', serif;
  font-size: 18px;
  font-style: italic;
  padding: 4px 0 8px;
}
.where {
  margin: 0 0 20px;
  padding: 10px 18px 12px;
  background: rgba(0,0,0,0.025);
  border: 1px solid var(--rule);
  border-left: 2px solid var(--ink);
  border-top: none;
}
.where .wlab {
  font-family: 'JetBrains Mono', monospace;
  font-size: 10px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  display: block;
  margin-bottom: 6px;
}
.where ul { list-style: none; margin: 0; padding: 0; }
.where li {
  padding: 5px 0;
  font-size: 14px;
  line-height: 1.5;
  color: var(--soft);
  border-top: 1px dotted var(--rule);
}
.where li:first-child { border-top: none; }
.where li b { color: var(--ink); font-weight: 600; font-family: 'JetBrains Mono', monospace; font-size: 12px; }

/* Per-section "Remember" */
.key {
  margin: 18px 0 0;
  padding: 12px 16px;
  border-left: 3px solid var(--accent);
  background: linear-gradient(90deg, rgba(200,16,46,0.05), transparent 70%);
}
.key .lab {
  font-family: 'JetBrains Mono', monospace;
  font-size: 10px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--accent);
  display: block;
  margin-bottom: 4px;
}
.key p { margin: 0; font-size: 15px; }

/* "In one breath" closing */
.closing {
  margin-top: 24px;
  padding-top: 28px;
  border-top: 2px solid var(--ink);
  border-bottom: none;
}
.closing .chno { color: var(--soft); }
.breath {
  font-family: 'ET Serif Display', serif;
  font-size: 19px;
  line-height: 1.45;
  font-style: italic;
}

/* Cross-references */
.cross-refs {
  margin-top: 28px;
  padding-top: 16px;
  border-top: 1px solid var(--rule);
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  color: var(--soft);
}
.cross-refs .label {
  color: var(--accent);
  letter-spacing: 0.2em;
  text-transform: uppercase;
  font-size: 10px;
  margin-right: 8px;
}
.cross-refs a {
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px solid var(--rule);
  margin-right: 14px;
}
.cross-refs a:hover { border-bottom-color: var(--ink); }

footer {
  margin-top: 40px;
  padding-top: 16px;
  border-top: 1px solid var(--rule);
  font-family: 'JetBrains Mono', monospace;
  font-size: 10px;
  color: var(--soft);
  letter-spacing: 0.1em;
  display: flex;
  justify-content: space-between;
}
footer a { color: var(--ink); text-decoration: none; border-bottom: 1px solid var(--ink); }

@media (max-width: 640px) {
  .page { padding: 32px 24px; }
  header.title h1 { font-size: 28px; }
  header.title h1 .subtitle { font-size: 18px; }
  .breath { font-size: 17px; }
  .formula .eq { font-size: 16px; }
}