* { box-sizing: border-box; }
html, body {
  margin: 0;
  background: var(--ledger);
  color: var(--ink);
  font-family: 'Public Sans', system-ui, -apple-system, sans-serif;
}
body { font-size: 16px; line-height: 1.6; }

.page { max-width: 800px; margin: 0 auto; padding: 4.5rem 1.75rem 6rem; }

.masthead { margin-bottom: 3rem; }
.masthead__brand { display: flex; align-items: center; gap: 0.55rem; }
.masthead__icon { display: block; flex: none; }
.masthead__brand .masthead__kicker { margin: 0; }
.masthead__kicker {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--graphite);
  margin: 0;
}
.masthead__rule { width: 48px; height: 3px; background: var(--ink-blue); border: 0; margin: 0.9rem 0; }
.masthead__mark {
  font-family: 'Bitter', Georgia, serif;
  font-weight: 700;
  font-size: 2rem;
  margin: 0;
  text-wrap: balance;
}

.lede { font-size: 1.1rem; color: var(--ink); max-width: 68ch; margin: 0 0 3rem; text-wrap: balance; }

.section { padding-top: 2.25rem; border-top: 1px solid var(--rule); margin-top: 2.25rem; }
.section:first-of-type { border-top: none; padding-top: 0; margin-top: 0; }
.section__eyebrow {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-blue);
  margin: 0 0 0.4rem;
}
.section h2 { font-size: 1.3rem; font-weight: 600; margin: 0 0 0.9rem; }
.section > p { max-width: 70ch; margin: 0 0 1rem; }

code, .mono { font-family: 'IBM Plex Mono', monospace; }
.section code {
  font-size: 0.88em;
  background: var(--sheet);
  border: 1px solid var(--rule);
  border-radius: 3px;
  padding: 0.1em 0.35em;
}

/* Stack diagram */
.stack { display: flex; flex-direction: column; gap: 0; margin: 1.75rem 0; max-width: 480px; }
.stack__layer {
  background: var(--sheet);
  border: 1px solid var(--rule);
  border-radius: 4px;
  padding: 0.9rem 1.1rem;
  position: relative;
}
.stack__layer + .stack__layer { margin-top: 1.6rem; }
.stack__layer + .stack__layer::before {
  content: "↑ references";
  position: absolute;
  top: -1.5rem;
  left: 1.1rem;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.65rem;
  color: var(--graphite);
  letter-spacing: 0.03em;
}
.stack__name { font-weight: 600; font-size: 0.95rem; }
.stack__desc { font-size: 0.85rem; color: var(--graphite); margin-top: 0.15rem; }

/* Rules list */
ol.rules { list-style: none; margin: 1.5rem 0; padding: 0; display: flex; flex-direction: column; gap: 1.1rem; }
ol.rules li {
  display: grid;
  grid-template-columns: 2rem 1fr;
  gap: 0.85rem;
  max-width: 68ch;
}
ol.rules .rule-num {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.85rem;
  color: var(--ink-blue);
  padding-top: 0.1rem;
}
ol.rules .rule-content { display: flex; flex-direction: column; min-width: 0; }
ol.rules .rule-title { font-weight: 600; margin-bottom: 0.15rem; }
ol.rules .rule-body { color: var(--graphite); font-size: 0.93rem; }

.grid-two { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem 2.5rem; margin-top: 1.25rem; }
@media (max-width: 620px) { .grid-two { grid-template-columns: 1fr; } }
.feature h3 { font-size: 0.92rem; font-weight: 600; margin: 0 0 0.3rem; }
.feature p { margin: 0; color: var(--graphite); font-size: 0.9rem; max-width: 42ch; }

pre.snippet {
  background: var(--sheet);
  border: 1px solid var(--rule);
  border-radius: 4px;
  padding: 1.1rem 1.3rem;
  overflow-x: auto;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.82rem;
  line-height: 1.55;
  margin: 1.5rem 0;
  color: var(--ink);
}
pre.snippet .cmt { color: var(--graphite); }
pre.snippet .kw { color: var(--ink-blue); }

table.meta {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  font-size: 0.88rem;
}
table.meta th, table.meta td { text-align: left; padding: 0.5rem 0.7rem; border-bottom: 1px solid var(--rule); vertical-align: top; }
table.meta th {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.68rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--graphite);
  font-weight: 400;
  white-space: nowrap;
}

.callout {
  background: var(--sheet);
  border: 1px solid var(--rule);
  border-left: 3px solid var(--ink-blue);
  border-radius: 4px;
  padding: 1.3rem 1.5rem;
  margin: 2rem 0;
}
.callout p { margin: 0; max-width: 64ch; font-size: 0.94rem; }
.callout p + p { margin-top: 0.6rem; }

.back-link {
  display: inline-block;
  margin-top: 3rem;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.78rem;
  color: var(--ink-blue);
  text-decoration: none;
}
.back-link:hover, .back-link:focus-visible { text-decoration: underline; }

footer {
  margin-top: 0;
  padding-top: 1.5rem;
  border-top: 1px solid var(--rule);
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.72rem;
  color: var(--graphite);
}

@media (max-width: 520px) {
  .page { padding: 3rem 1.25rem 4rem; }
  .masthead__mark { font-size: 1.6rem; }
}