/* ==========================================================================
   CCAI — Cumulative Certified Autonomous Intelligence
   Design system v1 — institutional / scientific
   Self-contained. No external resources. CSP-compatible (no inline styles).
   ========================================================================== */

:root {
  --paper:      #FBFBF8;
  --paper-2:    #F4F4EE;
  --ink:        #1B1B18;
  --ink-soft:   #3C3C36;
  --muted:      #5E5E57;
  --faint:      #8A8A82;
  --accent:     #1E3D59;
  --accent-ink: #16304A;
  --hairline:   #E3E3DA;
  --hairline-2: #D4D4C9;
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, "Source Serif Pro",
           Georgia, "Times New Roman", serif;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue",
          Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", "Cascadia Mono", Menlo, Consolas,
          "Liberation Mono", monospace;
  --measure: 44rem;
  --wide: 62rem;
  --gutter: clamp(1.25rem, 4vw, 2.5rem);
}

/* ---------- Reset / base ---------- */

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 5.5rem;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 1.0625rem;
  line-height: 1.65;
  font-kerning: normal;
  text-rendering: optimizeLegibility;
}

::selection { background: #DCE5EE; }

a {
  color: var(--accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
}
a:hover { color: var(--accent-ink); }

a:focus-visible,
[tabindex]:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 1px;
}

p { margin: 0 0 1.15em; max-width: var(--measure); }

strong { font-weight: 650; }

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--ink);
  color: var(--paper);
  padding: 0.6rem 1rem;
  z-index: 100;
  font-size: 0.9rem;
}
.skip-link:focus { left: 0.5rem; top: 0.5rem; }

/* ---------- Header / navigation ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--paper);
  border-bottom: 1px solid var(--hairline);
}

.header-inner {
  max-width: var(--wide);
  margin: 0 auto;
  padding: 0.85rem var(--gutter);
  display: flex;
  align-items: baseline;
  gap: 1.5rem;
}

.wordmark {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 1.3rem;
  letter-spacing: 0.14em;
  color: var(--ink);
  text-decoration: none;
  white-space: nowrap;
}
.wordmark:hover { color: var(--accent); }

.site-nav { overflow-x: auto; scrollbar-width: none; }
.site-nav::-webkit-scrollbar { display: none; }

.site-nav ul {
  display: flex;
  gap: 1.35rem;
  list-style: none;
  margin: 0;
  padding: 0;
  white-space: nowrap;
}

.site-nav a {
  color: var(--ink-soft);
  text-decoration: none;
  font-size: 0.86rem;
  letter-spacing: 0.01em;
}
.site-nav a:hover { color: var(--accent); text-decoration: underline; text-underline-offset: 0.25em; }

/* ---------- Layout ---------- */

main { display: block; }

.section {
  max-width: var(--wide);
  margin: 0 auto;
  padding: clamp(3.5rem, 8vw, 6rem) var(--gutter) 0;
}

.section:last-of-type { padding-bottom: clamp(3.5rem, 8vw, 6rem); }

.section-head { max-width: var(--measure); margin-bottom: 2.2rem; }

.section-index {
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.22em;
  color: var(--faint);
  display: block;
  margin-bottom: 0.9rem;
}

h1, h2, h3, h4 {
  font-family: var(--serif);
  font-weight: 700;
  line-height: 1.15;
  color: var(--ink);
}

h2 {
  font-size: clamp(1.65rem, 3.4vw, 2.15rem);
  margin: 0 0 0.5rem;
  letter-spacing: -0.01em;
}

h3 {
  font-size: 1.28rem;
  margin: 2.4rem 0 0.6rem;
}

.lede {
  font-size: 1.16rem;
  line-height: 1.6;
  color: var(--ink-soft);
}

.rule-top { border-top: 1px solid var(--hairline); }

/* ---------- Hero ---------- */

.hero {
  max-width: var(--wide);
  margin: 0 auto;
  padding: clamp(4.5rem, 11vw, 8.5rem) var(--gutter) clamp(3rem, 7vw, 5rem);
}

.hero-eyebrow {
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 1.6rem;
}

.hero h1 {
  font-size: clamp(4rem, 12vw, 7.5rem);
  letter-spacing: 0.12em;
  margin: 0 0 0.4rem;
  line-height: 1;
}

.hero-expansion {
  font-family: var(--serif);
  font-size: clamp(1.25rem, 3.2vw, 1.8rem);
  color: var(--ink-soft);
  margin: 0 0 2.2rem;
  letter-spacing: 0.01em;
}

.hero-tagline {
  font-size: clamp(1.05rem, 2.2vw, 1.22rem);
  line-height: 1.6;
  color: var(--ink-soft);
  max-width: 40rem;
  margin: 0 0 3.2rem;
}

/* ---------- The canonical quatrain ---------- */

.quatrain {
  border-left: 3px solid var(--ink);
  padding: 0.4rem 0 0.4rem 1.6rem;
  margin: 0;
}

.quatrain p {
  font-family: var(--serif);
  font-size: clamp(1.3rem, 3vw, 1.75rem);
  line-height: 1.55;
  margin: 0;
  max-width: none;
  color: var(--ink);
}

.quatrain .q-final { font-weight: 700; color: var(--accent-ink); }

.quatrain-fig figcaption {
  margin-top: 1.1rem;
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--faint);
}

/* Wide treatment used in the Architecture section */
.quatrain-fig.feature {
  background: var(--paper-2);
  border-top: 1px solid var(--hairline);
  border-bottom: 1px solid var(--hairline);
  padding: clamp(2.5rem, 6vw, 4.5rem) var(--gutter);
  margin: 2.8rem calc(-1 * var(--gutter)) 0;
}
.quatrain-fig.feature .quatrain { max-width: 40rem; margin: 0 auto; }
.quatrain-fig.feature figcaption { text-align: center; }

/* ---------- Definition block ---------- */

.definition {
  border-top: 1px solid var(--hairline-2);
  border-bottom: 1px solid var(--hairline-2);
  padding: 1.8rem 0 0.4rem;
  margin: 2rem 0;
}

.definition p {
  font-family: var(--serif);
  font-size: 1.16rem;
  line-height: 1.7;
  max-width: 62ch;
}

.note {
  font-size: 0.95rem;
  color: var(--muted);
}

.note::before {
  content: "— ";
  color: var(--faint);
}

/* ---------- Lists ---------- */

ul.plain, ol.plain { max-width: var(--measure); padding-left: 1.3rem; }
ul.plain li, ol.plain li { margin-bottom: 0.5em; }

/* ---------- The canonical loop diagram ---------- */

.loop-wrap {
  margin: 2.6rem 0 1rem;
  display: flex;
  justify-content: flex-start;
}

.loop {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  align-items: stretch;
  min-width: min(100%, 26rem);
}

.loop li { position: relative; }

.loop .stage {
  display: block;
  font-family: var(--mono);
  font-size: 0.92rem;
  letter-spacing: 0.14em;
  text-align: center;
  padding: 0.85rem 1.4rem;
  border: 1px solid var(--hairline-2);
  background: var(--paper);
  color: var(--ink);
}

.loop .stage-num {
  color: var(--faint);
  margin-right: 0.9em;
  font-size: 0.78rem;
  letter-spacing: 0.1em;
}

/* connector arrows between stages */
.loop li + li::before {
  content: "↓";
  display: block;
  text-align: center;
  color: var(--faint);
  font-size: 1rem;
  line-height: 1.9;
}

.loop .decision { border-color: var(--ink); border-width: 1px; }
.loop .decision > .stage { border: none; padding-bottom: 0.5rem; font-weight: 700; }

.loop .outcomes {
  display: flex;
  gap: 0.5rem;
  justify-content: center;
  padding: 0 0.8rem 0.8rem;
  flex-wrap: wrap;
}

.chip {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  padding: 0.32rem 0.7rem;
  border: 1px solid var(--hairline-2);
  background: var(--paper-2);
  color: var(--ink-soft);
  white-space: nowrap;
}
.chip.certified { border-color: var(--accent); color: var(--accent-ink); background: #EDF2F7; }

.loop-return {
  margin-top: 1.1rem;
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.1em;
  color: var(--muted);
  text-align: center;
}

/* ---------- Epistemic states ---------- */

.states {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 15rem), 1fr));
  gap: 1px;
  background: var(--hairline);
  border: 1px solid var(--hairline);
  margin: 2.2rem 0;
}

.state {
  background: var(--paper);
  padding: 1.5rem 1.4rem 1.3rem;
}

.state h3 {
  font-family: var(--mono);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  margin: 0 0 0.7rem;
  color: var(--accent-ink);
}

.state p { font-size: 0.95rem; margin: 0; color: var(--ink-soft); }

.outcomes-row {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin: 1.6rem 0 1.2rem;
}

.outcome {
  flex: 1 1 12rem;
  border: 1px solid var(--hairline-2);
  padding: 1.1rem 1.2rem;
  background: var(--paper);
}
.outcome h4 {
  font-family: var(--mono);
  font-size: 0.82rem;
  letter-spacing: 0.2em;
  margin: 0 0 0.55rem;
}
.outcome p { font-size: 0.92rem; margin: 0; color: var(--ink-soft); }
.outcome.certified { border-color: var(--accent); }
.outcome.certified h4 { color: var(--accent-ink); }

.callout {
  border-left: 3px solid var(--accent);
  background: var(--paper-2);
  padding: 1.1rem 1.4rem;
  margin: 1.8rem 0;
  max-width: var(--measure);
}
.callout p { margin: 0 0 0.6em; font-size: 0.98rem; }
.callout p:last-child { margin-bottom: 0; }

/* ---------- Progression chain (cumulative) ---------- */

.chain {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.55rem 0.6rem;
  margin: 2rem 0;
  padding: 0;
  list-style: none;
}

.chain li {
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.1em;
  color: var(--ink-soft);
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.chain li + li::before { content: "→"; color: var(--faint); }

.chain .node {
  border: 1px solid var(--hairline-2);
  background: var(--paper);
  padding: 0.5rem 0.8rem;
  white-space: nowrap;
}
.chain .node.key { border-color: var(--accent); color: var(--accent-ink); background: #EDF2F7; }

/* ---------- Comparison (what CCAI is not) ---------- */

.compare {
  border-top: 1px solid var(--hairline);
  margin: 2rem 0;
  max-width: var(--wide);
}

.compare-row {
  display: grid;
  grid-template-columns: minmax(10rem, 16rem) 1fr;
  gap: 1.2rem;
  padding: 1.05rem 0;
  border-bottom: 1px solid var(--hairline);
}

.compare-row dt {
  font-family: var(--mono);
  font-size: 0.88rem;
  letter-spacing: 0.04em;
  color: var(--ink);
  font-weight: 700;
}

.compare-row dd { margin: 0; color: var(--ink-soft); font-size: 0.97rem; max-width: 46rem; }

@media (max-width: 40rem) {
  .compare-row { grid-template-columns: 1fr; gap: 0.3rem; }
}

/* ---------- Charter ---------- */

.charter-head {
  border: 1px solid var(--hairline-2);
  background: var(--paper-2);
  padding: 1.6rem 1.8rem;
  margin-bottom: 2.6rem;
  max-width: var(--measure);
}
.charter-head p { margin: 0 0 0.5em; font-size: 0.95rem; color: var(--ink-soft); }
.charter-head p:last-child { margin-bottom: 0; }
.charter-head .version {
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.2em;
  color: var(--accent-ink);
  text-transform: uppercase;
}

.article {
  max-width: var(--measure);
  padding: 1.9rem 0 1.7rem;
  border-top: 1px solid var(--hairline);
}
.article:first-of-type { border-top: none; padding-top: 0.5rem; }

.article-label {
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.24em;
  color: var(--faint);
  text-transform: uppercase;
  display: block;
  margin-bottom: 0.55rem;
}

.article h3 {
  margin: 0 0 0.8rem;
  font-size: 1.22rem;
}

.article p { color: var(--ink-soft); }
.article p:last-child { margin-bottom: 0; }

/* ---------- Reference implementation ---------- */

.impl-box {
  border: 1px solid var(--hairline-2);
  padding: 1.8rem 2rem;
  max-width: var(--measure);
  background: var(--paper);
}
.impl-box p { color: var(--ink-soft); }

.distinction {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: var(--hairline);
  border: 1px solid var(--hairline);
  margin: 1.6rem 0 0;
  max-width: var(--measure);
}
.distinction > div { background: var(--paper); padding: 1.1rem 1.2rem; }
.distinction h4 {
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.18em;
  margin: 0 0 0.5rem;
  color: var(--accent-ink);
}
.distinction p { margin: 0; font-size: 0.92rem; }

@media (max-width: 40rem) {
  .distinction { grid-template-columns: 1fr; }
}

/* ---------- Charter page specifics ---------- */

.charter-title {
  font-size: clamp(2.2rem, 5vw, 3.2rem);
  margin: 0 0 0.5rem;
}

.charter-end { margin-top: 2.5rem; }

/* ---------- Footer ---------- */

.site-footer {
  border-top: 1px solid var(--hairline);
  margin-top: clamp(3rem, 7vw, 5rem);
}

.footer-inner {
  max-width: var(--wide);
  margin: 0 auto;
  padding: 2.2rem var(--gutter) 3rem;
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 2.5rem;
  align-items: baseline;
  justify-content: space-between;
}

.footer-inner .f-id {
  font-family: var(--serif);
  font-size: 0.98rem;
  color: var(--ink-soft);
}

.footer-inner nav ul {
  display: flex;
  gap: 1.4rem;
  list-style: none;
  margin: 0;
  padding: 0;
  flex-wrap: wrap;
}
.footer-inner nav a {
  font-size: 0.85rem;
  color: var(--muted);
  text-decoration: none;
}
.footer-inner nav a:hover { color: var(--accent); text-decoration: underline; }

.f-note {
  width: 100%;
  font-size: 0.82rem;
  color: var(--faint);
  margin: 0.6rem 0 0;
}

/* ---------- Subtle motion (opt-in only) ---------- */

@media (prefers-reduced-motion: no-preference) {
  a, .site-nav a { transition: color 140ms ease-out; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

/* ---------- Small screens ---------- */

@media (max-width: 34rem) {
  body { font-size: 1rem; }
  .header-inner { flex-direction: column; align-items: flex-start; gap: 0.55rem; padding-top: 0.7rem; padding-bottom: 0.7rem; }
  html { scroll-padding-top: 7.5rem; }
  .quatrain { padding-left: 1.1rem; }
  .impl-box { padding: 1.3rem 1.2rem; }
}

/* ---------- Print (Charter-friendly) ---------- */

@media print {
  .site-header, .site-footer nav, .skip-link, .f-note { display: none; }
  body { background: #fff; color: #000; font-size: 11pt; }
  .section, .hero { padding-top: 1.2rem; padding-bottom: 0; }
  a { color: #000; text-decoration: none; }
  .article { break-inside: avoid; }
  .quatrain-fig.feature { background: #fff; margin: 1rem 0 0; }
  .states, .distinction { border-color: #bbb; background: #bbb; }
  h1 { font-size: 28pt; }
}