:root {
  --color-bg: #f0efe9;
  --color-surface: #ffffff;
  --color-primary: #0f1923;
  --color-primary-soft: #334556;
  --color-amber: #e8a020;
  --color-subtext: #6b7280;
  --color-border: #d1cec8;
  --color-energy: #e8a020;
  --color-metals: #4a90d9;
  --color-agri: #5ba85c;
  --nav-height: 52px;
  --shell-max: 1180px;
  --reading-max: 780px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--color-primary);
  background:
    radial-gradient(circle at top left, rgba(232, 160, 32, 0.14), transparent 28%),
    linear-gradient(180deg, rgba(255, 255, 255, 0.5), rgba(255, 255, 255, 0)),
    var(--color-bg);
}

a {
  color: inherit;
}

.nav {
  position: sticky;
  top: 0;
  z-index: 120;
  min-height: var(--nav-height);
  display: flex;
  align-items: center;
  padding: 8px 24px;
  background: var(--color-primary);
}

.nav-logo {
  font-family: var(--font-serif);
  font-weight: 400;
  font-size: 19px;
  color: #fff;
  letter-spacing: 0.02em;
  white-space: nowrap;
  user-select: none;
}

.nav-logo .dot {
  display: inline-block;
  width: 5px;
  height: 5px;
  margin-left: 3px;
  border-radius: 50%;
  background: var(--color-amber);
  vertical-align: middle;
  position: relative;
  top: -1px;
}

.page-shell {
  width: min(var(--shell-max), calc(100vw - 48px));
  margin: 0 auto;
  padding: 36px 0 84px;
}

.hero {
  position: relative;
  overflow: hidden;
  padding: 32px 32px 30px;
  border: 1px solid rgba(15, 25, 35, 0.1);
  border-radius: 18px;
  background:
    linear-gradient(135deg, rgba(255, 255, 255, 0.94), rgba(255, 255, 255, 0.84)),
    rgba(255, 255, 255, 0.9);
  box-shadow: 0 18px 50px rgba(15, 25, 35, 0.08);
}

.hero::after {
  content: "";
  position: absolute;
  inset: auto -80px -110px auto;
  width: 240px;
  height: 240px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(232, 160, 32, 0.18), rgba(232, 160, 32, 0));
  pointer-events: none;
}

.hero-kicker {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-subtext);
}

.hero-title {
  max-width: 14ch;
  margin: 0;
  font-family: var(--font-serif);
  font-size: var(--type-display);
  line-height: 1.02;
  letter-spacing: 0;
}

.hero-summary {
  max-width: 58rem;
  margin: 18px 0 0;
  font-size: 1rem;
  line-height: 1.72;
  color: var(--color-primary-soft);
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 22px;
}

.hero-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border: 1px solid rgba(15, 25, 35, 0.1);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.68);
  color: var(--color-primary-soft);
  font-size: 12px;
}

.hero-chip .dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--color-amber);
}

.content-stack {
  display: grid;
  gap: 24px;
  margin-top: 26px;
}

.content-grid {
  display: grid;
  grid-template-columns: minmax(0, 260px) minmax(0, 1fr);
  gap: 24px;
  align-items: start;
  margin-top: 26px;
}

.content-main {
  display: grid;
  gap: 18px;
}

.content-card,
.toc-card {
  border: 1px solid rgba(15, 25, 35, 0.1);
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.9);
  box-shadow: 0 12px 34px rgba(15, 25, 35, 0.05);
}

.content-card {
  padding: 28px 28px 30px;
}

.content-card.is-reading {
  max-width: var(--reading-max);
}

.content-card h2,
.content-card h3 {
  margin: 0;
  font-family: var(--font-serif);
}

.section-kicker {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-subtext);
}

.section-title {
  font-size: var(--type-section-title);
  line-height: 1.15;
}

.section-title.with-anchor {
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.section-anchor {
  color: var(--color-subtext);
  text-decoration: none;
  opacity: 0;
  transition: opacity 150ms ease, color 150ms ease;
}

.content-card:hover .section-anchor,
.content-card:focus-within .section-anchor {
  opacity: 1;
}

.section-anchor:hover {
  color: var(--color-amber);
}

.lede {
  margin: 14px 0 0;
  color: var(--color-primary-soft);
  line-height: 1.7;
}

.prose {
  margin-top: 18px;
  color: var(--color-primary-soft);
  line-height: 1.75;
}

.prose p {
  margin: 0 0 16px;
}

.prose p:last-child,
.prose ul:last-child,
.prose ol:last-child {
  margin-bottom: 0;
}

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

.prose ul,
.prose ol {
  margin: 0 0 16px;
  padding-left: 20px;
}

.prose li + li {
  margin-top: 10px;
}

.prose code {
  font-family: var(--font-mono);
  font-size: 0.92em;
  color: var(--color-primary);
}

.inline-link {
  color: var(--color-primary);
  text-decoration: none;
  border-bottom: 1px solid rgba(232, 160, 32, 0.6);
}

.inline-link:hover {
  border-bottom-color: var(--color-amber);
}

.module-grid,
.source-grid,
.policy-grid,
.formula-grid {
  display: grid;
  gap: 14px;
  margin-top: 18px;
}

.module-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.source-grid,
.policy-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.formula-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.module-card,
.source-card,
.policy-card,
.formula-card,
.note-card {
  padding: 18px;
  border: 1px solid rgba(15, 25, 35, 0.09);
  border-radius: 14px;
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.82), rgba(255, 255, 255, 0.66)),
    rgba(255, 255, 255, 0.85);
}

.module-card h3,
.source-card h3,
.policy-card h3,
.formula-card h3,
.note-card h3 {
  margin: 0 0 10px;
  font-family: var(--font-sans);
  font-size: 0.98rem;
  font-weight: 600;
  letter-spacing: 0.01em;
}

.module-card p,
.source-card p,
.policy-card p,
.formula-card p,
.note-card p {
  margin: 0;
  color: var(--color-primary-soft);
  line-height: 1.65;
  font-size: 0.95rem;
}

.module-status {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-bottom: 10px;
  color: var(--color-subtext);
  font-family: var(--font-mono);
  font-size: var(--type-meta);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.module-status .dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
}

.module-status .dot.energy {
  background: var(--color-energy);
}

.module-status .dot.metals {
  background: var(--color-metals);
}

.module-status .dot.agri {
  background: var(--color-agri);
}

.module-status .dot.neutral {
  background: rgba(15, 25, 35, 0.18);
}

.note-card {
  margin-top: 18px;
  border-left: 3px solid var(--color-amber);
}

.toc-card {
  position: sticky;
  top: calc(var(--nav-height) + 18px);
  padding: 18px;
}

.toc-title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-subtext);
}

.toc-list {
  display: grid;
  gap: 8px;
}

.toc-link {
  display: inline-flex;
  align-items: center;
  min-height: 34px;
  padding: 0 10px;
  border-radius: 10px;
  text-decoration: none;
  color: var(--color-primary-soft);
  background: transparent;
  transition: background-color 150ms ease, color 150ms ease;
}

.toc-link:hover,
.toc-link.is-active {
  color: var(--color-primary);
  background: rgba(232, 160, 32, 0.14);
}

.toc-link:focus-visible,
.inline-link:focus-visible,
.section-anchor:focus-visible,
.to-top-btn:focus-visible,
.hero-chip:focus-visible {
  outline: 2px solid rgba(15, 25, 35, 0.26);
  outline-offset: 2px;
}

.footer {
  width: min(var(--shell-max), calc(100vw - 48px));
  margin: 0 auto;
  padding: 0 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  color: var(--color-subtext);
  font-size: 12px;
}

.footer-left {
  font-size: 11px;
}

.footer-right {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.to-top-btn {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 85;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  border: 1px solid var(--color-primary);
  background: var(--color-amber);
  color: var(--color-primary);
  border-radius: 20px;
  padding: 7px 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.02em;
  line-height: 1;
  cursor: pointer;
  box-shadow: 0 3px 12px rgba(15, 25, 35, 0.22);
  opacity: 0;
  pointer-events: none;
  transform: translateY(10px);
  transition: opacity 170ms ease, transform 170ms ease, background 150ms ease;
}

.to-top-btn.visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

.to-top-btn:hover {
  background: #f0ab2d;
}

.to-top-btn svg {
  display: block;
  width: 12px;
  height: 12px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2.25;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

@media (max-width: 980px) {
  .content-grid,
  .module-grid,
  .source-grid,
  .policy-grid,
  .formula-grid {
    grid-template-columns: 1fr;
  }

  .toc-card {
    position: static;
  }
}

@media (max-width: 760px) {
  .nav {
    padding-left: 16px;
    padding-right: 16px;
  }

  .page-shell,
  .footer {
    width: min(var(--shell-max), calc(100vw - 32px));
  }

  .page-shell {
    padding-top: 22px;
  }

  .hero,
  .content-card,
  .toc-card {
    padding-left: 20px;
    padding-right: 20px;
  }

  .footer {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }

  .to-top-btn {
    right: 16px;
    bottom: 16px;
  }
}

@media (max-width: 640px) {
  :root {
    --nav-height: 96px;
  }

  .nav {
    min-height: 0;
    padding-top: 10px;
    padding-bottom: 10px;
    align-items: flex-start;
  }

  .page-shell {
    padding-bottom: 72px;
  }

  .hero {
    padding-top: 24px;
    padding-bottom: 24px;
  }

  .hero-title {
    max-width: 11ch;
  }
}

/* ── Typography contract alignment ─────────────────────────────────────── */
.hero-kicker,
.section-kicker,
.module-status,
.toc-title,
.toc-list a,
.footnote-list,
.footer-left,
.footer-right,
.to-top-btn {
  font-family: var(--font-mono);
  font-size: var(--type-meta);
  letter-spacing: var(--tracking-kicker);
  line-height: var(--leading-meta);
}

.hero-title {
  font-family: var(--font-serif);
  font-size: var(--type-display);
  line-height: var(--leading-tight);
  letter-spacing: var(--tracking-none);
}

.section-title {
  font-family: var(--font-serif);
  font-size: var(--type-section-title);
  line-height: var(--leading-title);
  letter-spacing: var(--tracking-none);
}

.hero-summary,
.lede,
.prose,
.module-card p,
.source-card p,
.policy-card p,
.formula-card p,
.note-card p {
  font-size: var(--type-body);
  line-height: var(--leading-readable);
}

.module-card h3,
.source-card h3,
.policy-card h3,
.formula-card h3,
.note-card h3 {
  font-family: var(--font-sans);
  font-size: var(--type-body-small);
  letter-spacing: var(--tracking-none);
  line-height: var(--leading-title);
}