/* Article copy is immediately readable. Scroll-triggered motion remains only inside explanatory visuals. */
  .js .reveal,
  .js .reveal.visible {
    opacity: 1 !important;
    transform: none !important;
    transition: none !important;
  }

  /* On wide screens every side illustration follows the same editorial rule: text left, visual right. */
  @media (min-width: 1081px) {
    .problem.has-visual,
    body.toc-collapsed .problem.has-visual {
      display: grid !important;
      grid-template-columns: minmax(0, var(--prose)) minmax(360px, var(--visual)) !important;
      column-gap: var(--main-gap) !important;
      align-items: start !important;
      direction: ltr !important;
    }

    .problem.has-visual::before,
    body.toc-collapsed .problem.has-visual::before {
      grid-column: 1 / -1 !important;
    }

    .problem.has-visual > :not(.problem-visual),
    body.toc-collapsed .problem.has-visual > :not(.problem-visual) {
      grid-column: 1 !important;
    }

    .problem.has-visual > .problem-visual,
    body.toc-collapsed .problem.has-visual > .problem-visual {
      grid-column: 2 !important;
      grid-row: 2 / span 100 !important;
      justify-self: stretch !important;
      margin-left: 0 !important;
      margin-right: 0 !important;
    }
  }

  /* Accessible role colors keep vivid accents for decoration and dark surfaces. */
  :root {
    --orange-text: #b33a1e;
    --mint-text: #0d7568;
    --meta-text: #565c65;
    --text-caption: .75rem;
    --text-detail: .8125rem;
  }

  main a:hover,
  footer a:hover,
  .rail a:hover { color: var(--orange-text); }

  .chapter-head .chapter-kicker,
  .problem-no,
  .arch-card .tag,
  .entity .index,
  .limits-field article > span,
  .lab-option em,
  .iceberg-top b,
  .gateway-node span,
  .machine span,
  .version-split b,
  .runtime-queue-title,
  .memory-ledger b,
  .local-queue b,
  .missing-tracks em,
  .memory-arrow,
  .toc-progress-label b,
  .toc-tree a.active span,
  .toc-tree .act-link span { color: var(--orange-text); }

  .toc-tree a span { color: var(--meta-text); }
  .toc-tree .group-link span { color: var(--mint-text); }

  /* Semantic heading order: h1 → act h2 → chapter h3 → item h4 → comparison h5. */
  h5 { margin-top: 0; }
  .glossary h2 { margin-bottom: 14px; font-size: .84rem; letter-spacing: .11em; text-transform: uppercase; }
  .chapter-head h3 {
    margin-bottom: 18px;
    font-size: clamp(2.2rem, 4.5vw, 4.6rem);
    line-height: 1.02;
    letter-spacing: -.052em;
  }
  .problem > h4 {
    margin-bottom: 20px;
    font-size: clamp(1.65rem, 3.2vw, 2.8rem);
    line-height: 1.1;
    letter-spacing: -.038em;
  }
  .compare-card h5 { margin-bottom: 10px; font-size: 1rem; }
  .group-conclusion h4 {
    max-width: 820px;
    margin-bottom: 18px;
    font-size: clamp(2rem, 4.5vw, 4rem);
    line-height: 1.03;
    letter-spacing: -.05em;
  }
  .root-cause h3 { max-width: 900px; color: #fff; }
  .entity h4 { margin: 10px 0 13px; font-size: 1.5rem; letter-spacing: -.03em; }
  .system-object > h3 { font-size: clamp(1.8rem, 3.4vw, 3rem); line-height: 1.08; letter-spacing: -.04em; }
  .review-path h4 {
    margin: 16px 0 12px;
    font-size: clamp(1.2rem, 2.3vw, 1.7rem);
    line-height: 1.12;
    letter-spacing: -.03em;
  }
  .rollout-step h4 { margin-bottom: 8px; font-size: 1.25rem; }
  .limits-field h4 { margin-bottom: 7px; font-size: 1.18rem; }
  .finale h3 {
    max-width: 900px;
    margin-bottom: 28px;
    font-size: clamp(2.7rem, 6vw, 6.4rem);
    line-height: .98;
    letter-spacing: -.06em;
  }

  /* Navigation and explanatory copy never render below a readable caption size. */
  .toc-hide,
  .toc-show-desktop,
  .toc-show-desktop b,
  .toc-progress-label,
  .toc-tree a span,
  .toc-tree .group-link,
  .toc-tree .problem-link,
  .toc-tree .section-link,
  .toc-tree .toc-root-link,
  .toc-tree .toc-intro,
  .toc-fab,
  .toc-fab b,
  .toc-drawer-head span,
  .toc-drawer .toc-tree a,
  .toc-drawer .toc-tree .problem-link,
  .eyebrow,
  .transform-label,
  .flow-unit b,
  .flow-unit small,
  .imbalance,
  .transform-bridge,
  .shared-properties span,
  .chapter-kicker,
  .quote small,
  .diagram-title,
  .pipeline-card span,
  .flow,
  .cost-equation .box small,
  .arch-card .tag,
  .entity .index,
  .chip,
  .verbs span,
  .hook-step span,
  .identity-level p,
  .review-question b,
  .review-path .label,
  .infra-item span,
  .case-thread span,
  .visual-label,
  .visual-caption,
  .problem-visual small,
  .lab-task small,
  .lab-option small,
  .lab-option b,
  .lab-option em,
  .worker-head small,
  .worker-head em,
  .metric-row,
  .metric-row strong,
  .metric-switch span,
  .cost-control label,
  .cost-control.rate,
  .cost-control output,
  .cost-control.rate b,
  .cost-result span,
  .waiting-time,
  .tank-shell b,
  .tank > span,
  .tank > small,
  .tank-pipe,
  .local-window b,
  .local-window span,
  .resource-meter,
  .local-queue,
  .artifact-source,
  .doc b,
  .doc small,
  .artifact-fog,
  .artifact-drawer b,
  .artifact-drawer span,
  .artifact-drawer small,
  .waterline span,
  .iceberg-top b,
  .iceberg-top span,
  .iceberg-under span,
  .gateway-node span,
  .gateway-node b,
  .gateway-node.human b,
  .direct-route,
  .machine span,
  .machine b,
  .machine small,
  .transfer-box b,
  .chat-top span,
  .bubble b,
  .zip,
  .version-split span,
  .version-split small,
  .audit-strip b,
  .audit-strip span,
  .missing-plugs span,
  .permission-grid > *,
  .permission-grid > b,
  .permission-grid > strong,
  .permission-legend span,
  .runtime-head span,
  .runtime-head b,
  .runtime-load,
  .runtime-queue-title,
  .folklore-note,
  .memory-counters span,
  .memory-counters small,
  .memory-ledger span,
  .cost-total,
  .memory-card small,
  .memory-card ul,
  .workspace-points span,
  .workspace-panel-head span,
  .workspace-row small,
  .workspace-tags span,
  .replay-screen span,
  .replay-screen small,
  .replay-controls em,
  .missing-tracks span,
  .memory-island b,
  .memory-island span,
  .memory-arrow span,
  .memory-graph > b,
  .memory-graph .node,
  .transition-counts span,
  .transition-operation-flow span,
  .proof-points span,
  .fallback-sidebar,
  .fallback-sidebar b,
  .fallback-board b,
  .product-proof figcaption,
  .product-detail figcaption,
  .product-detail figcaption b { font-size: var(--text-caption); }

  .visual-verdict,
  .bubble,
  .bubble b,
  .cost-lines span,
  .cost-takeaway span,
  .support-chat-notes span,
  .memory-feed span,
  .folklore-note,
  .visual-folklore .bubble b,
  .memory-ledger span { font-size: var(--text-detail); }

  .toc-tree a,
  .toc-drawer .toc-tree a { grid-template-columns: 58px minmax(0, 1fr); }

  a:focus-visible,
  button:focus-visible,
  summary:focus-visible,
  [tabindex]:focus-visible {
    outline: 3px solid var(--orange-text);
    outline-offset: 4px;
  }

  .source-link {
    color: var(--orange-text);
    font-weight: 800;
    text-decoration-thickness: .09em;
  }
  .source-link::after { content: " ↗"; font-size: .72em; }

  .license-note {
    margin-top: 16px;
    padding-top: 14px;
    border-top: 1px solid rgba(13,117,104,.2);
  }
  .license-note summary {
    width: fit-content;
    cursor: pointer;
    color: var(--ink);
    font-weight: 800;
  }
  .license-note summary::marker { color: var(--mint-text); }
  .license-note p {
    margin: 12px 0 0;
    color: #3d4645;
    font-size: .82rem;
    line-height: 1.55;
  }
  .license-note a { color: var(--orange-text); font-weight: 800; }

  .visible .metric-row > i b { min-width: 4px; }

  .visual-cost { min-height: 600px; }
  .cost-scenario h5 {
    margin: 0 0 12px;
    font-size: 1rem;
    line-height: 1.25;
  }
  .cost-scenario.immediate {
    border-color: rgba(var(--orange-rgb),.34);
    background: linear-gradient(145deg, rgba(var(--orange-rgb),.12), rgba(255,255,255,.86));
  }
  .cost-scenario.deferred {
    border-color: rgba(var(--mint-rgb),.46);
    background: linear-gradient(145deg, rgba(var(--mint-rgb),.18), rgba(255,255,255,.86));
  }
  .cost-factors {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
  }
  .cost-factors span {
    padding: 7px 9px;
    border: 1px solid rgba(21,23,27,.11);
    border-radius: 999px;
    background: rgba(255,255,255,.72);
    color: var(--muted);
    font-size: var(--text-caption);
    line-height: 1.25;
  }
  .cost-takeaway span b {
    display: block;
    margin-bottom: 4px;
    color: var(--ink);
  }

  /* The restored task-tracker lifecycle keeps its number, stage and explanation in distinct columns. */
  .timeline {
    display: grid;
    gap: 10px;
  }
  .timeline-row {
    display: grid;
    grid-template-columns: 40px minmax(130px, 150px) minmax(0, 1fr);
    align-items: start;
    gap: 14px;
    padding: 13px 15px;
    border: 1px solid var(--line);
    border-radius: 14px;
    background: rgba(255,255,255,.82);
    font-size: var(--text-detail);
    line-height: 1.45;
  }
  .timeline-row > .tno {
    color: var(--orange-text);
    font-weight: 850;
    font-variant-numeric: tabular-nums;
  }
  .timeline-row > b {
    min-width: 0;
    color: var(--ink);
    line-height: 1.35;
  }
  .timeline-row > span:last-child {
    min-width: 0;
    color: var(--muted);
  }
  .timeline-mask {
    margin-top: 16px;
    padding: 14px 16px;
    border-radius: 13px;
    background: var(--orange);
    color: #111;
    text-align: center;
    font-size: var(--text-detail);
    font-weight: 850;
    line-height: 1.4;
  }

  /* Addenda extend a problem without blending into its original argument. */
  .problem-note {
    margin: 30px 0 12px;
    padding: 22px 24px;
    border-inline-start: 3px solid var(--mint-text);
    border-radius: 0 18px 18px 0;
    background: rgba(var(--mint-rgb),.1);
    color: var(--ink);
  }
  .problem-note-label {
    display: block;
    margin-bottom: 12px;
    color: var(--mint-text);
    font-size: var(--text-caption);
    font-weight: 850;
    letter-spacing: .11em;
    text-transform: uppercase;
  }
  .problem-note p {
    margin: 0;
    color: var(--ink);
    font-size: .9rem;
    line-height: 1.65;
  }
  .problem-note p + p,
  .problem-note p + ul,
  .problem-note ul + p {
    margin-top: 14px;
  }
  .problem-note ul {
    margin-bottom: 0;
    padding-inline-start: 1.25rem;
    color: var(--ink);
    font-size: .88rem;
    line-height: 1.55;
  }
  .problem-note li + li {
    margin-top: 5px;
  }
  .problem-note li::marker {
    color: var(--orange-text);
  }

  .visual-investment {
    min-height: 610px;
    background:
      radial-gradient(circle at 8% 12%, rgba(var(--orange-rgb),.16), transparent 34%),
      radial-gradient(circle at 94% 78%, rgba(var(--mint-rgb),.2), transparent 38%),
      rgba(255,255,255,.7);
  }
  .decision-question {
    padding: 18px;
    border: 1px solid var(--line);
    border-radius: 18px;
    background: var(--night);
    color: #fff;
  }
  .decision-question small,
  .decision-question b { display: block; }
  .decision-question small {
    margin-bottom: 5px;
    color: var(--mint);
    font-weight: 800;
    letter-spacing: .09em;
    text-transform: uppercase;
  }
  .decision-question b { font-size: 1rem; line-height: 1.3; }
  .decision-paths {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: 10px;
    align-items: stretch;
    margin-top: 16px;
  }
  .decision-path {
    padding: 15px;
    border: 1px solid var(--line);
    border-radius: 17px;
    background: rgba(255,255,255,.78);
  }
  .decision-path span,
  .decision-path b,
  .decision-path small { display: block; }
  .decision-path span {
    color: var(--muted);
    font-size: var(--text-caption);
    line-height: 1.3;
  }
  .decision-path b { margin: 10px 0 7px; font-size: .9rem; line-height: 1.18; }
  .decision-path small { color: var(--muted); line-height: 1.4; }
  .decision-path.systemic {
    border-color: rgba(var(--mint-rgb),.5);
    background: linear-gradient(145deg, rgba(var(--mint-rgb),.18), rgba(255,255,255,.84));
  }
  .decision-paths > i {
    align-self: center;
    color: var(--orange-text);
    font-size: var(--text-caption);
    font-style: normal;
    font-weight: 850;
  }
  .decision-criteria {
    display: flex;
    flex-wrap: wrap;
    gap: 7px;
    margin: 16px 0 92px;
  }
  .decision-criteria span {
    padding: 7px 9px;
    border-radius: 999px;
    background: rgba(21,23,27,.07);
    color: var(--muted);
    font-size: var(--text-caption);
    font-weight: 700;
  }

  .waterline {
    z-index: 5;
    pointer-events: none;
  }
  .waterline span {
    z-index: 6;
    top: -34px;
    padding: 5px 9px;
    border: 1px solid rgba(21,23,27,.1);
    border-radius: 999px;
    background: rgba(247,244,237,.96);
    box-shadow: 0 6px 16px rgba(13,16,22,.08);
  }
  .iceberg-top,
  .iceberg-under {
    position: relative;
    z-index: 1;
  }

  .language-switcher {
    position: fixed;
    z-index: 997;
    top: calc(18px + env(safe-area-inset-top));
    right: calc(18px + env(safe-area-inset-right));
    display: inline-flex;
    gap: 2px;
    padding: 4px;
    border: 1px solid rgba(255,255,255,.14);
    border-radius: 999px;
    background: rgba(12,15,20,.9);
    box-shadow: 0 18px 50px rgba(0,0,0,.22);
    backdrop-filter: blur(12px);
    font-size: .7rem;
    line-height: 1;
  }
  .language-switcher a {
    display: grid;
    min-width: 38px;
    min-height: 36px;
    padding: 0 10px;
    place-items: center;
    border-radius: 999px;
    color: rgba(255,255,255,.7);
    font-weight: 800;
    letter-spacing: .08em;
    text-decoration: none;
  }
  .language-switcher a:hover { color: #fff; }
  .language-switcher a[aria-current="page"] { background: #fff; color: var(--night); }
  .language-switcher a:focus-visible { outline: 2px solid var(--mint); outline-offset: 2px; }

  @media (max-width: 1280px) {
    .problem.has-visual,
    body.toc-collapsed .problem.has-visual {
      display: block !important;
      max-width: var(--prose) !important;
    }
    .problem.has-visual > .problem-visual,
    body.toc-collapsed .problem.has-visual > .problem-visual {
      position: relative !important;
      top: auto !important;
      width: min(620px, 100%) !important;
      margin: 44px 0 0 !important;
    }
    .toc-fab {
      right: calc(18px + env(safe-area-inset-right));
      bottom: calc(18px + env(safe-area-inset-bottom));
    }
    .toc-drawer {
      inset: auto calc(12px + env(safe-area-inset-right)) calc(12px + env(safe-area-inset-bottom)) auto;
      width: min(470px, calc(100% - 24px - env(safe-area-inset-left) - env(safe-area-inset-right)));
    }
  }

  @media (max-width: 680px) {
    .language-switcher {
      top: calc(12px + env(safe-area-inset-top));
      right: calc(12px + env(safe-area-inset-right));
    }
    h1 {
      max-width: 100%;
      font-size: clamp(2.2rem, 11.25vw, 3.65rem);
    }
    .timeline-row {
      grid-template-columns: 34px minmax(0, 1fr);
      gap: 4px 10px;
      padding: 12px;
    }
    .timeline-row > span:last-child {
      grid-column: 2;
    }
    .problem-note {
      margin-top: 24px;
      padding: 18px;
      border-radius: 0 15px 15px 0;
    }
    .problem-note p,
    .problem-note ul {
      font-size: .86rem;
    }
    .decision-paths { grid-template-columns: 1fr; }
    .decision-paths > i { justify-self: center; }
    .visual-investment { min-height: 740px; }
    .toc-fab {
      right: calc(12px + env(safe-area-inset-right));
      bottom: calc(12px + env(safe-area-inset-bottom));
    }
  }

  @media print {
    .language-switcher { display: none; }
  }