/* Cross-layer viewport adaptations remain last in the cascade. */

@media (max-width: 1280px) {
  .study-layout {
    display: block;
    max-width: none;
  }
  .chapter-rail { display: none; }
  .compact-study-tools {
    position: sticky;
    top: 0;
    z-index: 40;
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    border-bottom: 1px solid var(--line);
    background: var(--panel);
  }
  .chapter-menu,
  .notation-menu {
    position: static;
    display: block;
    min-width: 0;
    background: var(--panel);
  }
  .chapter-menu { border-right: 1px solid var(--line); }
  .chapter-menu summary,
  .notation-menu summary {
    display: grid;
    grid-template-columns: auto minmax(0, 1fr) auto;
    gap: 12px;
    align-items: baseline;
    min-height: 48px;
    padding: 13px 20px;
    color: var(--faint);
    font: 700 var(--font-size-metadata)/1.3 var(--sans-font);
    letter-spacing: .05em;
    text-transform: uppercase;
    cursor: pointer;
    list-style: none;
  }
  .chapter-menu summary::-webkit-details-marker,
  .notation-menu summary::-webkit-details-marker { display: none; }
  .chapter-menu summary strong,
  .notation-menu summary strong {
    min-width: 0;
    overflow: hidden;
    color: var(--ink);
    font-size: var(--font-size-technical);
    letter-spacing: .025em;
    text-overflow: ellipsis;
    white-space: nowrap;
  }
  .chapter-menu summary::after,
  .notation-menu summary::after {
    content: "+";
    color: var(--pink-text);
    font: 700 var(--font-size-technical) var(--mono-font);
  }
  .chapter-menu[open] summary::after,
  .notation-menu[open] summary::after { content: "−"; }
  .chapter-menu nav {
    position: absolute;
    top: 48px;
    right: 0;
    left: 0;
    max-height: calc(100vh - 48px);
    overflow-y: auto;
    border-top: 1px solid var(--line);
    background: var(--panel);
    box-shadow: 0 12px 24px rgb(41 40 36 / .12);
  }
  .chapter-menu .section-navigation-list {
    width: calc(100% - 40px);
    max-width: var(--max);
    margin-inline: auto;
  }
  .chapter-menu .chapter-navigation-list {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 1px;
    width: 100%;
    max-width: var(--max);
    margin-inline: auto;
    border-top: 0;
    background: var(--line);
  }
  .chapter-menu .chapter-navigation-link {
    height: 100%;
    min-height: 48px;
    border-bottom: 0;
    background: var(--panel);
  }
  .notation-menu > .notation-key {
    position: absolute;
    top: 48px;
    right: 0;
    left: 0;
    max-height: calc(100vh - 48px);
    margin: 0;
    padding: 18px 20px 20px;
    overflow-y: auto;
    border-top: 1px solid var(--line);
    background: var(--panel);
    box-shadow: 0 12px 24px rgb(41 40 36 / .12);
  }
  .notation-key-compact .notation-key-header {
    max-width: var(--max);
    margin-inline: auto;
  }
  .notation-key-compact .notation-key-list {
    display: grid;
    grid-template-columns: repeat(6, minmax(0, 1fr));
    gap: 1px;
    max-width: var(--max);
    margin-inline: auto;
    border: 1px solid var(--line);
    background: var(--line);
  }
  .notation-key-compact .notation-key-item {
    height: 100%;
    min-height: 52px;
    border: 0;
    background: var(--panel);
  }
  .notation-key-compact .notation-key-detail {
    max-width: var(--max);
    margin-inline: auto;
  }
}

@media (min-width: 1281px) and (max-height: 800px) {
  .chapter-rail {
    padding: 18px 12px 14px;
  }
  .chapter-rail-kicker {
    margin-bottom: 7px;
  }
  .chapter-navigation-link {
    min-height: 30px;
    padding: 7px 8px;
  }
  .notation-key-rail {
    margin-top: 12px;
    padding-top: 9px;
  }
  .notation-key-rail .notation-key-header {
    margin-bottom: 6px;
  }
  .notation-key-rail .notation-key-item {
    padding: 5px 8px;
  }
}

@media (max-width: 1050px) {
  .paper-body { margin-left: 0; }
  .argument-grid { grid-template-columns: 1fr; }
  .argument-grid:has(> article:nth-child(4):last-child) {
    grid-template-columns: 1fr;
  }
  .argument-grid article + article { border-left: 0; border-top: 1px solid var(--line); }
  .review-grid:has(> article:nth-child(4):last-child) {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .source-map { grid-template-columns: 1fr; }
  .source-map > li:nth-child(even) { border-left: 0; }
  .decision-columns { grid-template-columns: repeat(2, 1fr); }
  .decision-columns section:nth-child(3) { border-left: 0; }
  .decision-columns section:nth-child(n+3) { border-top: 1px solid var(--line); }
  .hero-index { grid-template-columns: repeat(3, 1fr); }
  .hero-index a + a { border-left: 1px solid var(--line); }
  .hero-index a:nth-child(3n + 1) { border-left: 0; }
  .hero-index a:nth-child(n+4) { border-top: 1px solid var(--line); }
  .run-trace-stage {
    display: block;
  }
  .run-trace-detail {
    display: grid;
    grid-template-columns: 1fr;
    gap: 12px;
    margin-top: 9px;
  }
  .run-trace-detail > p:first-child,
  .run-trace-invariant {
    grid-area: auto;
  }
}

@media (max-width: 900px) {
  .recovery-sequence {
    grid-template-columns: 1fr;
    gap: 34px;
  }
  .recovery-sequence > li {
    min-height: 128px;
    padding: 18px;
  }
  .recovery-sequence > li:not(:last-child)::after {
    top: auto;
    right: auto;
    bottom: -27px;
    left: 50%;
    content: "↓";
    transform: translateX(-50%);
  }
  .recovery-crash {
    min-height: 172px;
  }
  .recovery-survival { display: block; }
  .recovery-durable-bridge { display: none; }
}

@media (max-width: 760px) {
  .shell { width: calc(100% - 28px); }
  .hero { padding-top: 60px; }
  .hero-feedback {
    align-items: flex-start;
    flex-direction: column;
    gap: 4px;
  }
  .paper-section { padding: 76px 0; }
  .chapter-head { grid-template-columns: 1fr; gap: 6px; }
  .chapter-title-block { grid-column: 1; }
  .paper-body {
    --wide-overhang: 0px;
    grid-template-columns: 0 minmax(0, 1fr) 0;
    column-gap: 0;
  }
  .case-layout { grid-template-columns: 1fr; }
  .decision-record > header { grid-template-columns: 1fr; gap: 5px; }
  .recovery-lab-header { grid-template-columns: 1fr; }
  .recovery-facts {
    min-width: 0;
    padding: 18px 0 0;
    border-top: 1px solid var(--line);
    border-left: 0;
  }
  .hero-index { grid-template-columns: 1fr 1fr; }
  .hero-index a + a { border-left: 1px solid var(--line); }
  .hero-index a:nth-child(odd) { border-left: 0; }
  .hero-index a:nth-child(n+3) { border-top: 1px solid var(--line); }
  .technical-block { padding: 0; }
  .review-grid { grid-template-columns: 1fr; }
  .review-grid:has(> article:nth-child(4):last-child) {
    grid-template-columns: 1fr;
  }
  .source-map > li {
    grid-template-columns: 28px minmax(0, 1fr);
    gap: 4px 10px;
    padding-inline: 0;
  }
  .source-map > li::before { grid-row: 1 / 3; }
  .source-map b,
  .source-map code { grid-column: 2; }
  .ruled-definitions > div,
  .plane-list > div,
  .term-list > div {
    grid-template-columns: 1fr;
    gap: 7px;
  }
  .comparison-list { grid-template-columns: 1fr; }
  .comparison-list > div + div {
    border-top: 1px solid var(--line);
    border-left: 0;
  }
  .process-branch { grid-template-columns: 1fr; }
  .process-branch section { padding-right: 0; }
  .process-branch section + section {
    padding-left: 0;
    border-top: 1px solid var(--line);
    border-left: 0;
  }
  .content-table-wrap::before {
    content: "Scroll horizontally to inspect all columns";
    display: block;
    position: sticky;
    left: 0;
    width: max-content;
    margin-bottom: 8px;
    color: var(--faint);
    font: var(--font-size-metadata)/1.4 var(--mono-font);
  }
  .content-table { min-width: 700px; }
  .content-table:has(thead th:nth-child(2):last-child) {
    min-width: 560px;
  }
  .content-table-wrap:has(.evidence-layer-table)::before { display: none; }
  .evidence-layer-table {
    min-width: 0;
  }
  .evidence-layer-table thead {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
  }
  .evidence-layer-table tbody,
  .evidence-layer-table tr,
  .evidence-layer-table th,
  .evidence-layer-table td {
    display: block;
    width: 100%;
  }
  .evidence-layer-table tbody tr {
    padding: 18px 0 20px;
    border-top: 1px solid var(--line);
  }
  .evidence-layer-table tbody tr:first-child {
    border-top: 0;
  }
  .evidence-layer-table tbody th,
  .evidence-layer-table tbody td {
    min-width: 0;
    padding: 0;
    border: 0;
  }
  .evidence-layer-table tbody th {
    margin-bottom: 14px;
    font-size: var(--font-size-card-title);
  }
  .evidence-layer-table tbody td + td { margin-top: 13px; }
  .evidence-layer-table tbody td::before {
    display: block;
    margin-bottom: 4px;
    color: var(--faint);
    font: 700 var(--font-size-metadata)/1.3 var(--sans-font);
    letter-spacing: .06em;
    text-transform: uppercase;
  }
  .evidence-layer-table tbody td:nth-of-type(1)::before {
    content: "Durable objects";
  }
  .evidence-layer-table tbody td:nth-of-type(2)::before {
    content: "Purpose";
  }
  .evidence-layer-table tbody td:nth-of-type(3)::before {
    content: "Authority rule";
  }
  .typeset-diagram figcaption { grid-template-columns: 1fr; gap: 5px; }
  .typeset-diagram figcaption .diagram-kicker { grid-row: auto; }
  .diagram-scroll-hint { display: block; }
  .diagram-kicker { grid-row: auto; }
  .settlement-timeline-list {
    --timeline-rail: 48px;
    padding: 20px 12px;
  }
  .settlement-timeline-list::before {
    top: 41px;
    bottom: 41px;
    left: calc(12px + var(--timeline-rail) / 2);
  }
  .settlement-timeline-item,
  .settlement-timeline-transition {
    column-gap: 10px;
  }
  .settlement-timeline-marker {
    width: 40px;
    height: 40px;
  }
  .settlement-timeline-stage { padding: 15px 14px 16px; }
  .settlement-timeline-stage header {
    grid-template-columns: 1fr;
    gap: 5px;
  }
  .settlement-timeline-stage header > span { padding-top: 0; }
  .settlement-timeline-transition { min-height: 44px; }
  .chapter-menu .chapter-navigation-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .chapter-outline-list,
  .chapter-menu .section-navigation-list {
    grid-template-columns: 1fr;
  }
  .chapter-outline-list > li:nth-child(even),
  .section-navigation-list > li:nth-child(even) {
    border-left: 0;
  }
  .notation-map figcaption {
    grid-template-columns: 1fr;
    gap: 5px;
  }
  .notation-map figcaption .diagram-kicker { grid-row: auto; }
  .notation-map-rows { padding-inline: 14px; }
  .notation-map-row {
    grid-template-columns: 1fr;
    gap: 5px;
    padding-block: 14px;
  }
  .notation-map-flow {
    margin-inline: -4px;
    padding-bottom: 8px;
  }
  .notation-map-row-settlement .notation-map-flow {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
    overflow: visible;
    row-gap: 3px;
  }
  .notation-map-row-settlement .notation-map-node {
    width: 110px;
    justify-self: center;
  }
  .notation-map-row-settlement .notation-map-flow > :nth-child(n+4) {
    grid-column: 1 / -1;
  }
  .notation-map-row-settlement .notation-map-transition {
    min-height: 42px;
  }
  .notation-map-row-settlement .notation-map-transition b {
    transform: rotate(90deg);
  }
  .notation-popover {
    top: auto !important;
    right: 14px;
    bottom: 14px;
    left: 14px !important;
    width: auto;
  }
  .notation-key-compact .notation-key-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (max-width: 500px) {
  h1 { font-size: var(--font-size-document-title); }
  .hero-provenance { grid-template-columns: 1fr; }
  .hero-provenance > div {
    padding: 0;
  }
  .hero-provenance > div + div {
    margin-top: 8px;
    padding-top: 8px;
    border-top: 1px solid var(--line);
    border-left: 0;
  }
  .decision-columns { grid-template-columns: 1fr; }
  .decision-columns section + section { border-left: 0; border-top: 1px solid var(--line); }
  .hero-index { grid-template-columns: 1fr; }
  .hero-index a + a { border-left: 0; border-top: 1px solid var(--line); }
  .recovery-lab-header,
  .recovery-trace { padding-inline: 16px; }
  .process-list > li {
    grid-template-columns: 36px minmax(0, 1fr);
    gap: 13px;
  }
  .process-list::before { left: 17px; }
  .process-list > li::before {
    width: 36px;
    height: 36px;
  }
  .projection-flow { padding: 18px 14px; }
  .projection-flow-split { grid-template-columns: 1fr; }
  .projection-flow-split > p { text-align: left; }
  .chapter-menu .chapter-navigation-list { grid-template-columns: 1fr; }
  .notation-menu summary strong { display: none; }
  .notation-key-compact .notation-key-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
}