.upgrade-hero {
  position: relative;
  overflow: hidden;
}

.upgrade-hero::after {
  position: absolute;
  inset: auto 0 0;
  height: 3px;
  background: linear-gradient(90deg, var(--violet) 0 42%, var(--teal-deep) 42% 70%, var(--line) 70%);
  content: "";
}

.hero-kicker {
  margin: 0 0 0.75rem;
  color: var(--violet);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 650;
  letter-spacing: 0.13em;
}

.upgrade-boundary {
  margin-top: 0;
}

.opening-section {
  padding-top: 1rem;
}

.chapter-marker,
.chapter-divider {
  font-family: var(--font-mono);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.chapter-marker {
  display: flex;
  align-items: baseline;
  gap: 0.8rem;
  margin: 0 0 1.35rem;
  color: var(--ink-soft);
  font-size: 0.72rem;
}

.chapter-marker span,
.chapter-divider span {
  color: var(--violet);
  font-weight: 700;
}

.opening-lede {
  max-width: 66ch;
  color: var(--ink);
  font-size: clamp(1.16rem, 1.7vw, 1.42rem);
  font-weight: 470;
  line-height: 1.55;
}

.premise-equation {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin: 2rem 0;
  border-block: 1px solid var(--line);
}

.premise-equation > div {
  padding: 1.1rem;
}

.premise-equation > div + div {
  border-left: 1px solid var(--line);
}

.premise-equation span,
.contract-label {
  color: var(--violet);
  font-family: var(--font-mono);
  font-size: 0.67rem;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.premise-equation strong {
  display: block;
  margin-top: 0.55rem;
  color: var(--ink);
  font-size: 0.94rem;
}

.premise-equation p {
  margin: 0.45rem 0 0;
  color: var(--ink-soft);
  font-size: 0.82rem;
  line-height: 1.5;
}

.premise-rule {
  margin: 2.2rem 0 0;
  padding: clamp(1.3rem, 3vw, 2rem);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: color-mix(in oklch, var(--violet) 8%, var(--paper));
  color: var(--ink);
  font-size: clamp(1.2rem, 2.2vw, 1.65rem);
  font-weight: 590;
  line-height: 1.35;
}

.reload-spectrum {
  margin: 1.5rem 0;
  overflow-x: auto;
}

.reload-spectrum table {
  width: 100%;
  min-width: 49rem;
  border-collapse: collapse;
  font-size: 0.82rem;
}

.reload-spectrum th,
.reload-spectrum td {
  padding: 0.8rem 0.85rem;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

.reload-spectrum th {
  color: var(--ink);
  background: color-mix(in oklch, var(--violet) 7%, var(--paper));
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.reload-spectrum td {
  color: var(--ink-soft);
}

.reload-spectrum td:first-child {
  color: var(--ink);
  font-weight: 620;
}

.continuity-points {
  margin: 1.6rem 0;
  padding: 0;
  border-block: 1px solid var(--line);
  list-style: none;
}

.continuity-points li {
  display: grid;
  grid-template-columns: 3.2rem minmax(0, 1fr);
  gap: 1rem;
  padding: 1rem 0;
}

.continuity-points li + li {
  border-top: 1px solid var(--line);
}

.continuity-points li > span {
  color: var(--violet);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 700;
}

.continuity-points strong {
  color: var(--ink);
}

.continuity-points p {
  margin: 0.3rem 0 0;
  color: var(--ink-soft);
}

.continuity-contract {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin: 1.75rem 0;
  border-block: 1px solid var(--line);
}

.continuity-contract > div {
  padding: 1.1rem;
}

.continuity-contract > div + div {
  border-left: 1px solid var(--line);
  background: color-mix(in oklch, var(--teal) 7%, transparent);
}

.continuity-contract ul {
  margin: 0.8rem 0 0;
  padding-left: 1.15rem;
}

.continuity-contract li {
  color: var(--ink-soft);
  font-size: 0.85rem;
}

.upgrade-story {
  margin: 1.8rem 0;
  padding: 1.2rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: color-mix(in oklch, var(--violet) 4%, var(--paper));
}

.upgrade-story figcaption {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1rem;
  color: var(--ink-soft);
  font-size: 0.78rem;
}

.upgrade-story figcaption strong {
  color: var(--ink);
  font-size: 0.9rem;
}

.upgrade-story ol {
  margin: 0;
  padding: 0;
  list-style: none;
}

.upgrade-story li {
  display: grid;
  grid-template-columns: 3.2rem minmax(0, 1fr) 9rem;
  gap: 1rem;
  align-items: baseline;
  padding: 0.9rem 0;
  border-top: 1px solid var(--line);
}

.upgrade-story li::before {
  position: absolute;
}

.upgrade-story .story-index {
  color: var(--violet);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 700;
}

.upgrade-story strong {
  color: var(--ink);
}

.upgrade-story p {
  margin: 0.25rem 0 0;
  color: var(--ink-soft);
  font-size: 0.84rem;
}

.upgrade-story small {
  color: var(--ink-soft);
  font-family: var(--font-mono);
  font-size: 0.65rem;
  text-align: right;
}

.upgrade-story .story-branch {
  background: color-mix(in oklch, var(--violet) 6%, transparent);
}

.upgrade-story .story-promote {
  background: color-mix(in oklch, var(--teal) 10%, transparent);
}

.upgrade-story .story-promote .story-index {
  color: var(--teal-deep);
}

.readiness-checklist {
  margin: 1.5rem 0;
}

.readiness-checklist dl {
  margin: 0;
}

.readiness-checklist dl > div {
  display: grid;
  grid-template-columns: minmax(9rem, 0.32fr) minmax(0, 1fr);
  gap: 1.2rem;
  padding: 0.9rem 0;
  border-top: 1px solid var(--line);
}

.readiness-checklist dl > div:last-child {
  border-bottom: 1px solid var(--line);
}

.readiness-checklist dt {
  color: var(--ink);
  font-weight: 620;
}

.readiness-checklist dd {
  margin: 0;
  color: var(--ink-soft);
}

.chapter-divider {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  margin: clamp(4rem, 8vw, 7rem) 0 1rem;
  padding-block: 1rem;
  border-block: 1px solid var(--line);
  color: var(--ink-soft);
  font-size: 0.72rem;
}

.chapter-divider b {
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 620;
  letter-spacing: normal;
  text-transform: none;
}

.upgrade-figure figcaption {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.15rem;
  color: var(--ink-soft);
  font-size: 0.78rem;
}

.upgrade-figure figcaption strong {
  color: var(--ink);
  font-size: 0.92rem;
  font-weight: 610;
}

.upgrade-figure svg {
  min-width: 43rem;
}

.upgrade-figure .diagram-label {
  fill: var(--ink-soft);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.035em;
}

.upgrade-figure .diagram-line-violet,
.upgrade-figure .diagram-line-teal,
.upgrade-figure .no-transfer,
.upgrade-figure .lifeline,
.upgrade-figure .artifact-return {
  fill: none;
  stroke-width: 2;
}

.upgrade-figure .diagram-line-violet {
  stroke: var(--violet);
}

.upgrade-figure .diagram-line-teal {
  stroke: var(--teal-deep);
}

.upgrade-figure .no-transfer {
  stroke: var(--danger, oklch(50% 0.14 25));
  stroke-dasharray: 7 6;
}

.upgrade-figure .lifeline {
  stroke: var(--line);
  stroke-dasharray: 4 7;
}

.upgrade-figure .artifact-return {
  stroke: var(--teal-deep);
  stroke-dasharray: 6 5;
}

.upgrade-figure .active-marker {
  fill: color-mix(in oklch, var(--teal) 11%, var(--paper));
  stroke: var(--teal-deep);
}

.upgrade-figure .retired {
  opacity: 0.68;
}

.transfer-ledger {
  margin: 1.5rem 0;
  border-block: 1px solid var(--line);
}

.ledger-heading,
.ledger-row {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.ledger-heading span,
.ledger-row span {
  padding: 0.82rem 1rem;
}

.ledger-heading {
  color: var(--ink);
  background: color-mix(in oklch, var(--violet) 8%, var(--paper));
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 650;
  letter-spacing: 0.055em;
  text-transform: uppercase;
}

.ledger-heading span:last-child {
  background: color-mix(in oklch, var(--teal) 10%, transparent);
}

.ledger-row {
  border-top: 1px solid var(--line);
  color: var(--ink-soft);
  font-size: 0.88rem;
}

.ledger-heading span + span,
.ledger-row span + span {
  border-left: 1px solid var(--line);
}

.inheritance-map,
.hook-contracts {
  margin: 1.5rem 0;
}

.inheritance-map dl,
.hook-contracts dl {
  margin: 0;
}

.inheritance-map dl > div,
.hook-contracts dl > div {
  display: grid;
  grid-template-columns: minmax(9rem, 0.35fr) minmax(0, 1fr);
  gap: 1.2rem;
  padding: 0.85rem 0;
  border-top: 1px solid var(--line);
}

.inheritance-map dl > div:last-child,
.hook-contracts dl > div:last-child {
  border-bottom: 1px solid var(--line);
}

.inheritance-map dt,
.hook-contracts dt {
  color: var(--ink);
  font-weight: 620;
}

.inheritance-map dd,
.hook-contracts dd {
  margin: 0;
  color: var(--ink-soft);
}

.generation-rail {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  margin: 2rem 0;
  padding: 0;
  list-style: none;
}

.generation-rail li {
  position: relative;
  min-width: 0;
  padding: 2.2rem 0.6rem 0;
  border-top: 2px solid var(--line);
  text-align: center;
}

.generation-rail li + li {
  margin-top: 0;
}

.generation-rail li::before {
  position: absolute;
  top: -0.42rem;
  left: calc(50% - 0.36rem);
  width: 0.72rem;
  height: 0.72rem;
  border: 2px solid var(--paper);
  border-radius: 50%;
  background: var(--violet);
  box-shadow: 0 0 0 1px var(--violet);
  content: "";
}

.generation-rail li:nth-child(n + 4)::before {
  background: var(--teal-deep);
  box-shadow: 0 0 0 1px var(--teal-deep);
}

.generation-rail span {
  display: block;
  margin-bottom: 0.35rem;
  color: var(--ink-faint);
  font-family: var(--font-mono);
  font-size: 0.66rem;
}

.generation-rail strong,
.generation-rail small {
  display: block;
}

.generation-rail strong {
  color: var(--ink);
  font-size: 0.82rem;
}

.generation-rail small {
  margin-top: 0.25rem;
  color: var(--ink-soft);
  font-size: 0.7rem;
  line-height: 1.3;
}

.canary-bands {
  margin: 1.6rem 0;
  border-block: 1px solid var(--line);
}

.native-boundary {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin: 1.5rem 0;
  border-block: 1px solid var(--line);
}

.native-boundary > div {
  padding: 1rem;
}

.native-boundary > div + div {
  border-left: 1px solid var(--line);
  background: color-mix(in oklch, var(--teal) 7%, transparent);
}

.native-boundary span {
  color: var(--violet);
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 650;
  letter-spacing: 0.08em;
}

.native-boundary p {
  margin: 0.55rem 0 0;
  color: var(--ink-soft);
  font-size: 0.84rem;
}

.canary-bands > div {
  display: grid;
  grid-template-columns: 8.5rem minmax(10rem, 0.7fr) minmax(0, 1fr);
  align-items: baseline;
  gap: 1rem;
  padding: 1rem 0;
}

.canary-bands > div + div {
  border-top: 1px solid var(--line);
}

.canary-bands span,
.procedure-strip span {
  color: var(--violet);
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 650;
  letter-spacing: 0.08em;
}

.canary-bands > div:last-child span {
  color: var(--teal-deep);
}

.canary-bands strong {
  color: var(--ink);
  font-size: 0.9rem;
}

.canary-bands p {
  margin: 0;
  color: var(--ink-soft);
  font-size: 0.86rem;
}

.operations-table {
  margin: 1.5rem 0;
  overflow-x: auto;
}

.operations-table table {
  width: 100%;
  min-width: 42rem;
  border-collapse: collapse;
  font-size: 0.84rem;
}

.operations-table th,
.operations-table td {
  padding: 0.75rem 0.85rem;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

.operations-table th {
  color: var(--ink);
  background: color-mix(in oklch, var(--violet) 7%, var(--paper));
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.operations-table td {
  color: var(--ink-soft);
}

.operations-table td:first-child {
  color: var(--ink);
  font-weight: 620;
}

.procedure-strip {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  margin: 1.75rem 0;
  border-block: 1px solid var(--line);
}

.procedure-strip > div {
  padding: 1rem;
}

.procedure-strip > div + div {
  border-left: 1px solid var(--line);
}

.procedure-strip p {
  margin: 0.55rem 0 0;
  color: var(--ink-soft);
  font-size: 0.8rem;
  line-height: 1.5;
}

.source-disclosure {
  margin: 1.5rem 0;
  border: 1px solid var(--line);
  border-radius: var(--radius-small);
  background: color-mix(in oklch, var(--violet) 3%, var(--paper));
}

.source-disclosure > summary {
  padding: 0.9rem 1rem;
  color: var(--ink);
  cursor: pointer;
  font-weight: 650;
}

.source-disclosure > p,
.source-disclosure > .api-source-map,
.source-disclosure > figure {
  margin-right: 1rem;
  margin-left: 1rem;
}

.api-source-map dd p {
  margin: 0;
}

.source-disclosure > figure:last-child {
  margin-bottom: 1rem;
}

.version-pair {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}

.version-pair > figure {
  min-width: 0;
  margin: 0;
}

@media (max-width: 780px) {
  .premise-equation {
    grid-template-columns: 1fr;
  }

  .premise-equation > div + div {
    border-top: 1px solid var(--line);
    border-left: 0;
  }

  .upgrade-story li {
    grid-template-columns: 2.6rem minmax(0, 1fr);
  }

  .upgrade-story small {
    grid-column: 2;
    text-align: left;
  }

  .generation-rail {
    grid-template-columns: repeat(3, 1fr);
    row-gap: 2rem;
  }

  .canary-bands > div {
    grid-template-columns: 1fr;
    gap: 0.4rem;
  }

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

  .procedure-strip > div:nth-child(3) {
    border-left: 0;
    border-top: 1px solid var(--line);
  }

  .procedure-strip > div:nth-child(4) {
    border-top: 1px solid var(--line);
  }

  .version-pair {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 560px) {
  .upgrade-figure figcaption {
    align-items: flex-start;
    flex-direction: column;
    gap: 0.25rem;
  }

  .ledger-heading,
  .ledger-row,
  .native-boundary,
  .continuity-contract,
  .readiness-checklist dl > div,
  .inheritance-map dl > div,
  .hook-contracts dl > div {
    grid-template-columns: 1fr;
  }

  .native-boundary > div + div {
    border-top: 1px solid var(--line);
    border-left: 0;
  }

  .continuity-contract > div + div {
    border-top: 1px solid var(--line);
    border-left: 0;
  }

  .ledger-heading span + span,
  .ledger-row span + span {
    border-top: 1px dashed var(--line);
    border-left: 0;
  }

  .generation-rail {
    grid-template-columns: repeat(2, 1fr);
  }

  .procedure-strip {
    grid-template-columns: 1fr;
  }

  .procedure-strip > div + div,
  .procedure-strip > div:nth-child(3) {
    border-top: 1px solid var(--line);
    border-left: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  .upgrade-hero::after {
    background: var(--line);
  }
}