/* ============================================================
   layout.css — page structure: hero, sections, two-column grid,
   discussion, glossary, references, footer
   ============================================================ */

main {
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 24px 64px;
}

/* ============ hero ============ */

.hero {
  padding: 72px 0 32px;
  text-align: center;
}

.hero .kicker {
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--accent-deep);
  margin: 0 0 18px;
}

.hero h1 {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(34px, 5.5vw, 56px);
  line-height: 1.08;
  letter-spacing: -0.015em;
  margin: 0 0 14px;
}

.hero .byline {
  font-size: 15px;
  color: var(--text-soft);
  margin: 0 0 22px;
}

.hero .lede {
  max-width: 720px;
  margin: 0 auto 12px;
  font-size: 16.5px;
  color: var(--text-soft);
}

.hero .status {
  display: inline-block;
  font-size: 13px;
  color: var(--text-soft);
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 6px 14px;
  margin: 4px 0 0;
}

.hero .status .dot {
  color: var(--accent);
  margin: 0 4px;
}

/* ============ legend ============ */

.legend {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 8px 16px;
  margin: 8px 0 8px;
  padding: 12px 18px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-elev);
  font-size: 12.5px;
  color: var(--text-soft);
}

.legend-title {
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 11px;
  color: var(--text-faint);
}

.legend-item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.lg-swatch {
  display: inline-block;
  width: 12px;
  height: 12px;
  border-radius: 4px;
  border: 1px solid var(--border-strong);
}

.lg-term { background: var(--accent-soft); border-color: var(--accent); }
.lg-info { background: var(--note-info-bg); border-color: var(--note-info-border); }
.lg-why  { background: var(--note-why-bg); border-color: var(--note-why-border); }
.lg-warn { background: var(--note-warn-bg); border-color: var(--note-warn-border); }
.lg-disc { background: var(--disc-bg); border-color: var(--disc-border); }

/* ============ sections ============ */

.section {
  margin-top: 56px;
  padding-top: 8px;
  scroll-margin-top: calc(var(--header-h) + 12px);
  transition: opacity 0.3s;
}

.section-head {
  margin-bottom: 26px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 14px;
}

.section-head h2 {
  font-family: var(--font-serif);
  font-size: clamp(26px, 3.4vw, 36px);
  margin: 0 0 4px;
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.sec-num {
  color: var(--accent);
  font-family: var(--font-sans);
  font-size: 0.62em;
  font-weight: 800;
  border: 2px solid var(--accent);
  border-radius: 10px;
  padding: 1px 9px;
}

.section-tag {
  margin: 0;
  font-size: 13.5px;
  color: var(--text-faint);
  font-style: italic;
}

/* ============ paragraph + annotations two-column ============ */

.para {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
  gap: 36px;
  align-items: start;
  margin-top: 34px;
}

.text p {
  font-family: var(--font-serif);
  font-size: 17.5px;
  line-height: 1.75;
  margin: 0;
}

/* ============ diagrams (full width between paras) ============ */

.diagram {
  margin: 40px auto 8px;
}

/* ============ discussion ============ */

.discussion {
  margin-top: 44px;
  padding: 22px 26px 24px;
  background: var(--disc-bg);
  border: 1px solid var(--disc-border);
  border-radius: var(--radius);
}

.discussion h3 {
  margin: 0 0 12px;
  font-size: 15px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 8px;
}

.discussion h3::before {
  content: "💬";
  font-size: 15px;
}

.discussion ol {
  margin: 0;
  padding-left: 24px;
  display: grid;
  gap: 10px;
}

.discussion li {
  font-size: 15.5px;
  line-height: 1.6;
  padding-left: 2px;
}

.discussion li::marker {
  color: var(--accent-deep);
  font-weight: 800;
}

/* ============ next-up ============ */

.next-up {
  margin-top: 36px;
  padding: 16px 20px;
  border-left: 3px solid var(--accent);
  background: var(--bg-elev);
  border-radius: 0 var(--radius) var(--radius) 0;
  border-top: 1px solid var(--border);
  border-right: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.next-up p {
  margin: 0;
  font-size: 14.5px;
  color: var(--text-soft);
}

.next-up strong {
  color: var(--text);
}

/* ============ glossary ============ */

.glossary {
  margin-top: 72px;
  padding-top: 28px;
  border-top: 2px solid var(--border);
  scroll-margin-top: calc(var(--header-h) + 12px);
}

.glossary h2,
.references h2 {
  font-family: var(--font-serif);
  font-size: 30px;
  margin: 0 0 6px;
}

.glossary-lede,
.refs-note {
  color: var(--text-soft);
  font-size: 14px;
  margin: 0 0 22px;
}

.glossary dl {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px 40px;
  margin: 0;
}

.glossary dt {
  font-weight: 700;
  font-size: 15px;
  margin-bottom: 3px;
}

.glossary dt::marker {
  display: none;
}

.glossary dd {
  margin: 0;
  font-size: 14px;
  line-height: 1.6;
  color: var(--text-soft);
}

/* ============ references ============ */

.references {
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  scroll-margin-top: calc(var(--header-h) + 12px);
}

.references ol {
  margin: 0 0 14px;
  padding-left: 24px;
}

.references li {
  font-size: 14.5px;
}

.backref {
  text-decoration: none;
  font-weight: 700;
}

/* ============ footer ============ */

.site-footer {
  padding: 40px 24px 56px;
  border-top: 1px solid var(--border);
  background: var(--bg-sunken);
  text-align: center;
}

.site-footer p {
  max-width: 720px;
  margin: 0 auto 10px;
  font-size: 13.5px;
  color: var(--text-soft);
}

.site-footer .foot-links {
  margin-top: 18px;
  display: flex;
  justify-content: center;
  gap: 18px;
  flex-wrap: wrap;
}

/* ============ responsive ============ */

@media (max-width: 920px) {
  .hero { padding-top: 48px; }
  .para {
    grid-template-columns: 1fr;
    gap: 18px;
  }
  .notes {
    padding-left: 10px;
    border-left: 3px solid var(--border);
  }
  .glossary dl {
    grid-template-columns: 1fr;
  }
  .section-nav { display: none; }
  .header-inner { justify-content: space-between; }
}