.about-page {
  min-height: 100svh;
  overflow: auto;
  background: var(--canvas);
}

.about-shell {
  width: min(1080px, calc(100% - 40px));
  margin: 0 auto;
  padding: 20px 0 72px;
}

.about-nav {
  display: flex;
  min-height: 40px;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.about-nav .wordmark { color: var(--text); text-decoration: none; }

.doc-shell {
  width: min(100%, 780px);
  margin: 76px auto 0;
}

.doc-kicker {
  margin: 0 0 18px;
  color: var(--accent);
  font: 600 11px/1 var(--mono);
  letter-spacing: .12em;
}

.doc-shell h1 {
  max-width: 18ch;
  margin: 0;
  color: var(--text);
  font: 700 clamp(32px, 5vw, 48px)/1.12 var(--sans);
  letter-spacing: -.04em;
}

.doc-lede {
  max-width: 60ch;
  margin: 24px 0 0;
  color: var(--muted);
  font: 400 19px/1.55 var(--sans);
}

.doc-section {
  margin-top: 72px;
}

.doc-section h2 {
  margin: 0 0 18px;
  color: var(--text);
  font: 700 22px/1.25 var(--sans);
  letter-spacing: -.02em;
}

.doc-section p {
  max-width: 68ch;
  margin: 0 0 16px;
  color: var(--muted);
  font: 400 17px/1.72 var(--sans);
}

.doc-section p strong { color: var(--text); font-weight: 600; }

.doc-note,
.state-example,
.model-facts,
.project-contract,
.threshold-grid,
.use-block,
.comparison-block,
.control-loop,
.primitive-row {
  background: var(--field-raised);
  border-radius: var(--radius-md);
}

.doc-note {
  display: grid;
  gap: 8px;
  max-width: 68ch;
  margin-top: 24px;
  padding: 18px 20px;
  background: rgb(139 212 80 / 10%);
}

.doc-note strong,
.comparison-label,
.use-block strong {
  color: var(--accent);
  font: 600 11px/1.2 var(--mono);
  letter-spacing: .08em;
  text-transform: uppercase;
}

.doc-note span {
  color: var(--text);
  font: 500 16px/1.5 var(--sans);
}

.model-facts {
  display: grid;
  gap: 1px;
  max-width: 68ch;
  margin-top: 24px;
  padding: 8px;
}

.model-facts > div {
  display: grid;
  grid-template-columns: 100px minmax(0, 1fr);
  gap: 16px;
  align-items: baseline;
  padding: 12px;
  background: var(--prompt-surface);
  border-radius: var(--radius-sm);
}

.model-facts strong {
  color: var(--text);
  font: 600 12px/1.3 var(--mono);
}

.model-facts span {
  color: var(--muted);
  font: 400 14px/1.5 var(--sans);
}

.model-facts code {
  padding: 2px 5px;
  color: var(--accent);
  background: var(--field-raised);
  border-radius: 5px;
  font: 500 .9em/1 var(--mono);
}

.comparison-grid,
.use-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  max-width: 68ch;
  margin: 24px 0;
}

.comparison-block,
.use-block {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 8px;
  min-height: 150px;
  padding: 18px 20px;
}

.comparison-block p {
  margin: 0;
  font-size: 16px;
  line-height: 1.6;
}

.accent-block { background: rgb(139 212 80 / 10%); }
.accent-block .comparison-label { color: var(--accent); }

.state-example {
  display: grid;
  gap: 1px;
  max-width: 68ch;
  margin-top: 24px;
  padding: 8px;
}

.state-example > div,
.project-contract > div {
  display: grid;
  grid-template-columns: 130px minmax(0, 1fr);
  gap: 16px;
  align-items: baseline;
  padding: 12px;
  background: var(--prompt-surface);
  border-radius: var(--radius-sm);
}

.code-key,
.project-contract strong {
  color: var(--accent);
  font: 600 12px/1.3 var(--mono);
}

.code-value,
.project-contract span {
  color: var(--muted);
  font: 400 15px/1.45 var(--sans);
}

.primitive-list {
  display: grid;
  gap: 8px;
  max-width: 68ch;
  margin: 24px 0;
}

.primitive-row {
  display: grid;
  grid-template-columns: 150px minmax(0, 1fr) auto;
  gap: 18px;
  align-items: start;
  padding: 18px 20px;
}

.primitive-name {
  display: grid;
  gap: 5px;
}

.primitive-name strong {
  color: var(--text);
  font: 650 17px/1.25 var(--sans);
}

.primitive-name span {
  color: var(--dim);
  font: 500 11px/1.35 var(--mono);
}

.primitive-row p {
  margin: 0;
  font-size: 15px;
  line-height: 1.55;
}

.primitive-row code {
  align-self: center;
  padding: 7px 8px;
  color: var(--accent);
  background: var(--prompt-surface);
  border-radius: var(--radius-sm);
  font: 500 11px/1.2 var(--mono);
  white-space: nowrap;
}

.threshold-grid {
  display: grid;
  gap: 1px;
  max-width: 68ch;
  margin-top: 24px;
  padding: 8px;
}

.threshold-grid > div {
  display: grid;
  grid-template-columns: 210px minmax(0, 1fr);
  gap: 16px;
  padding: 13px 12px;
  background: var(--prompt-surface);
  border-radius: var(--radius-sm);
}

.threshold-grid strong {
  color: var(--text);
  font: 600 13px/1.35 var(--sans);
}

.threshold-grid span,
.use-block span {
  color: var(--muted);
  font: 400 14px/1.45 var(--sans);
}

.use-block strong { margin-bottom: 4px; }
.muted-block strong { color: var(--focus); }

.control-loop {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 1px;
  max-width: 900px;
  margin: 24px 0;
  padding: 8px;
}

.control-loop > div {
  display: flex;
  min-height: 154px;
  flex-direction: column;
  align-items: flex-start;
  gap: 8px;
  padding: 14px 12px;
  background: var(--prompt-surface);
  border-radius: var(--radius-sm);
}

.control-loop span {
  color: var(--accent);
  font: 600 11px/1 var(--mono);
}

.control-loop strong {
  color: var(--text);
  font: 600 14px/1.3 var(--sans);
}

.control-loop small {
  margin-top: auto;
  color: var(--muted);
  font: 400 12px/1.45 var(--sans);
}

.project-contract {
  display: grid;
  gap: 1px;
  max-width: 68ch;
  margin: 24px 0;
  padding: 8px;
}

.sources-section { padding-bottom: 64px; }

.source-list {
  display: grid;
  gap: 8px;
  max-width: 68ch;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.source-list li {
  display: grid;
  grid-template-columns: minmax(210px, auto) minmax(0, 1fr);
  gap: 16px;
  align-items: baseline;
  padding: 13px 14px;
  background: var(--field-raised);
  border-radius: var(--radius-sm);
}

.source-list a {
  color: var(--text);
  font: 600 14px/1.4 var(--sans);
  text-decoration-color: rgb(139 212 80 / 45%);
  text-underline-offset: 3px;
}

.source-list a:hover { color: var(--accent); }

.source-list span {
  color: var(--muted);
  font: 400 13px/1.45 var(--sans);
}

.doc-section code {
  padding: 2px 5px;
  color: #b4e38b;
  background: var(--field-raised);
  border-radius: 5px;
  font: 500 .9em/1 var(--mono);
}

.flow-diagram {
  display: grid;
  grid-template-columns: 1fr auto 1fr auto 1fr auto 1fr;
  gap: 8px;
  align-items: stretch;
  margin: 28px 0 0;
  padding: 0;
  list-style: none;
}

.flow-step {
  min-height: 132px;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 10px;
  padding: 16px;
  background: var(--field-raised);
  border-radius: var(--radius-md);
}

.flow-number {
  color: var(--accent);
  font: 600 11px/1 var(--mono);
  letter-spacing: .08em;
}

.flow-step strong {
  color: var(--text);
  font: 600 15px/1.25 var(--sans);
}

.flow-step > span:last-child {
  margin-top: auto;
  color: var(--muted);
  font: 400 13px/1.45 var(--sans);
}

.flow-arrow {
  display: grid;
  place-items: center;
  color: var(--dim);
  font: 400 20px/1 var(--sans);
}

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

.info-row {
  display: grid;
  grid-template-columns: 150px minmax(0, 1fr);
  gap: 20px;
  align-items: baseline;
  padding: 15px 16px;
  background: var(--prompt-surface);
  border-radius: var(--radius-md);
}

.info-row strong {
  color: var(--text);
  font: 600 11px/1.3 var(--mono);
  letter-spacing: .08em;
}

.info-row span {
  color: var(--muted);
  font: 400 15px/1.5 var(--sans);
}

@media (max-width: 760px) {
  .about-shell { width: min(100% - 32px, 620px); padding-top: 16px; }
  .doc-shell { margin-top: 56px; }
  .doc-section { margin-top: 60px; }
  .flow-diagram { grid-template-columns: 1fr 1fr; }
  .flow-arrow { display: none; }
  .info-row { grid-template-columns: 1fr; gap: 6px; }
  .comparison-grid,
  .use-grid { grid-template-columns: 1fr; }
  .primitive-row { grid-template-columns: 1fr; gap: 10px; }
  .primitive-row code { align-self: start; }
  .control-loop { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .state-example > div,
  .model-facts > div,
  .project-contract > div,
  .threshold-grid > div,
  .source-list li { grid-template-columns: 1fr; gap: 5px; }
}

@media (max-width: 480px) {
  .doc-shell h1 { font-size: 34px; }
  .doc-lede { font-size: 17px; }
  .doc-section { margin-top: 48px; }
  .flow-diagram { grid-template-columns: 1fr; }
  .doc-section p { font-size: 16px; }
  .control-loop { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  .about-link { transition: none; }
}