:root {
  --bg: #f7f6f2;
  --panel: #ffffff;
  --ink: #1d252c;
  --muted: #63717c;
  --line: #d9ded8;
  --accent: #225c58;
  --accent-2: #7d5330;
  --code-bg: #eef2f0;
  --sidebar: #edf1ee;
  --reference-glass-tint: #dcebe7;
  --reference-glass-highlight: #ffffff;
  --shadow: 0 14px 34px rgba(24, 35, 45, 0.08);
  font-family: "Segoe UI", "Noto Sans SC", "Microsoft YaHei", Arial, sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.72;
}

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid rgba(34, 92, 88, 0.26);
}

a:hover { border-bottom-color: var(--accent); }

.layout {
  display: grid;
  grid-template-columns: 300px minmax(0, 1fr);
  min-height: 100vh;
}

.sidebar {
  position: sticky;
  top: 0;
  height: 100vh;
  overflow: auto;
  padding: 24px 18px;
  border-right: 1px solid var(--line);
  background: var(--sidebar);
}

.brand {
  margin-bottom: 20px;
  color: #142027;
  font-size: 18px;
  font-weight: 750;
  line-height: 1.3;
}

.nav-section { margin: 22px 0; }

.nav-section h2 {
  margin: 0 0 8px;
  color: var(--muted);
  font-size: 12px;
  letter-spacing: 0;
  text-transform: uppercase;
}

.nav-section a {
  display: block;
  padding: 7px 8px;
  border: 0;
  border-radius: 6px;
  color: #26343d;
  font-size: 14px;
  line-height: 1.35;
}

.nav-section a:hover,
.nav-section a.active {
  background: rgba(34, 92, 88, 0.11);
  color: var(--accent);
}

.content-shell {
  min-width: 0;
  padding: 36px 44px 80px;
}

.content-shell.has-page-toc {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 270px;
  gap: 24px;
  align-items: start;
}

.content {
  max-width: 1120px;
  margin: 0 auto;
  padding: 34px 42px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: var(--shadow);
}

.content-shell.has-page-toc .content {
  max-width: none;
  margin: 0;
}

.page-title {
  margin: 0 0 18px;
  color: #142027;
  font-size: 30px;
  line-height: 1.25;
  font-weight: 760;
}

.meta {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 8px 18px;
  margin: 0 0 26px;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fbfbf8;
  color: var(--muted);
  font-size: 14px;
}

.meta b { color: #33414a; }

.page-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: -6px 0 22px;
}

.page-action-button {
  display: inline-flex;
  align-items: center;
  min-height: 36px;
  padding: 7px 12px;
  border: 1px solid rgba(34, 92, 88, 0.24);
  border-radius: 6px;
  background: #eef4f1;
  color: var(--accent);
  font-size: 14px;
  font-weight: 720;
}

.page-action-button:hover {
  border-color: rgba(34, 92, 88, 0.52);
  background: #e4efeb;
}

.proof-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 30px;
  margin-top: 8px;
  padding: 5px 10px;
  border: 1px solid rgba(34, 92, 88, 0.24);
  border-radius: 6px;
  background: #eef4f1;
  color: var(--accent);
  font-size: 13px;
  font-weight: 720;
}

.proof-link:hover {
  border-color: rgba(34, 92, 88, 0.5);
  background: #e3eeea;
}

.proof-target-flash {
  animation: proofTargetFlash 1.4s ease;
}

@keyframes proofTargetFlash {
  0% {
    box-shadow: 0 0 0 0 rgba(194, 116, 48, 0.42);
  }
  35% {
    box-shadow: 0 0 0 5px rgba(194, 116, 48, 0.16);
  }
  100% {
    box-shadow: none;
  }
}

.toc-sidebar {
  position: sticky;
  top: 24px;
  max-height: calc(100vh - 48px);
  overflow: auto;
}

.page-toc {
  margin: 0;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f9faf8;
}

.page-toc-title {
  margin: 0 0 8px;
  color: #33414a;
  font-size: 14px;
  font-weight: 700;
}

.page-toc ol {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-toc li { margin: 0; }

.page-toc a {
  border-bottom: 0;
  color: var(--accent);
  font-size: 14px;
}

.page-toc .toc-level-2 { padding-left: 14px; }
.page-toc .toc-level-2 a {
  color: var(--muted);
  font-size: 13px;
}

h1, h2, h3, h4 {
  color: #142027;
  line-height: 1.34;
}

h1 {
  margin-top: 34px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--line);
  font-size: 28px;
}

h2 {
  margin-top: 30px;
  font-size: 22px;
}

h3 {
  margin-top: 24px;
  font-size: 18px;
}

p, ul, ol, table, pre, blockquote { margin: 12px 0; }

table {
  width: 100%;
  border-collapse: collapse;
  overflow-wrap: anywhere;
  font-size: 14px;
}

th, td {
  padding: 8px 10px;
  border: 1px solid var(--line);
  vertical-align: top;
}

th {
  background: #eef3f1;
  font-weight: 680;
}

code {
  padding: 0.12em 0.3em;
  border-radius: 4px;
  background: var(--code-bg);
  font-family: "Cascadia Mono", Consolas, monospace;
  font-size: 0.92em;
}

pre {
  overflow-x: auto;
  padding: 14px 16px;
  border: 1px solid #d8ded8;
  border-left: 4px solid rgba(34, 92, 88, 0.55);
  border-radius: 8px;
  background: #f7faf8;
  color: #24313a;
  line-height: 1.62;
}

pre code {
  padding: 0;
  background: transparent;
  color: inherit;
  font-size: 0.94em;
}

blockquote {
  margin-left: 0;
  padding: 10px 16px;
  border-left: 4px solid var(--accent-2);
  background: #fbf8f4;
  color: #384852;
}

.concept-map {
  margin: 18px 0 26px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: linear-gradient(180deg, #fbfbf8 0%, #f3f6f4 100%);
}

.concept-root {
  padding: 18px 20px;
  border: 1px solid rgba(34, 92, 88, 0.18);
  border-radius: 8px;
  background: #ffffff;
}

.concept-root-title {
  color: #142027;
  font-size: 24px;
  font-weight: 780;
  line-height: 1.25;
}

.concept-root-subtitle {
  margin-top: 6px;
  color: var(--muted);
  font-size: 14px;
}

.concept-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  margin-top: 14px;
}

.concept-card {
  position: relative;
  min-height: 210px;
  padding: 18px 18px 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #ffffff;
}

.concept-card.wide {
  grid-column: 1 / -1;
  min-height: 0;
}

.concept-index {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 26px;
  border-radius: 999px;
  background: rgba(34, 92, 88, 0.10);
  color: var(--accent);
  font-size: 12px;
  font-weight: 760;
}

.concept-card h2 {
  margin: 12px 0 8px;
  border: 0;
  padding: 0;
  font-size: 19px;
}

.concept-card p {
  margin: 0 0 10px;
  color: var(--muted);
  font-size: 14px;
}

.concept-card ul {
  margin: 10px 0 0;
  padding-left: 18px;
}

.concept-card li {
  margin: 4px 0;
}

.concept-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.concept-tags span {
  padding: 5px 9px;
  border: 1px solid rgba(34, 92, 88, 0.18);
  border-radius: 999px;
  background: #f8faf8;
  color: #2d4549;
  font-size: 13px;
}

.matrix-concept-map {
  margin: 18px 0 28px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fbfbf8;
}

.matrix-map-core {
  display: grid;
  grid-template-columns: minmax(180px, 0.8fr) minmax(0, 1.2fr);
  gap: 16px;
  align-items: stretch;
  margin-bottom: 16px;
}

.matrix-map-question {
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 150px;
  padding: 18px;
  border: 1px solid rgba(34, 92, 88, 0.22);
  border-left: 5px solid var(--accent);
  border-radius: 8px;
  background: #ffffff;
}

.matrix-map-kicker {
  color: var(--accent);
  font-size: 13px;
  font-weight: 760;
}

.matrix-map-question strong {
  display: block;
  margin-top: 8px;
  color: #142027;
  font-size: 22px;
  line-height: 1.28;
}

.matrix-map-question span {
  display: block;
  margin-top: 8px;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.55;
}

.matrix-map-thesis {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
}

.matrix-map-thesis-item {
  min-height: 120px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #ffffff;
}

.matrix-map-thesis-item b {
  display: block;
  color: #142027;
  font-size: 15px;
}

.matrix-map-thesis-item span {
  display: block;
  margin-top: 7px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.52;
}

.matrix-map-flow {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
  align-items: stretch;
}

.matrix-map-stage {
  position: relative;
  min-height: 270px;
  padding: 14px 14px 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #ffffff;
}

.matrix-map-stage::after {
  content: "";
  position: absolute;
  top: 42px;
  right: -10px;
  width: 18px;
  height: 18px;
  border-top: 2px solid rgba(34, 92, 88, 0.32);
  border-right: 2px solid rgba(34, 92, 88, 0.32);
  transform: rotate(45deg);
  background: #fbfbf8;
}

.matrix-map-stage:last-child::after {
  display: none;
}

.matrix-map-stage[data-tone="linear"] { border-top: 4px solid #2f5f8f; }
.matrix-map-stage[data-tone="geometry"] { border-top: 4px solid #2f755a; }
.matrix-map-stage[data-tone="probability"] { border-top: 4px solid #8a3d5c; }
.matrix-map-stage[data-tone="application"] { border-top: 4px solid #9b6b23; }

.matrix-map-stage-label {
  color: var(--muted);
  font-size: 12px;
  font-weight: 760;
}

.matrix-map-stage h2 {
  margin: 7px 0 10px;
  border: 0;
  padding: 0;
  color: #142027;
  font-size: 18px;
}

.matrix-map-stage ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

.matrix-map-stage li {
  margin: 8px 0;
  padding: 9px 10px;
  border: 1px solid rgba(217, 222, 216, 0.9);
  border-radius: 6px;
  background: #f8faf8;
  color: #26343d;
  font-size: 14px;
  line-height: 1.45;
}

.matrix-map-stage li b {
  color: #142027;
}

.matrix-map-apps {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin-top: 14px;
}

.matrix-map-app {
  padding: 12px 14px;
  border: 1px solid rgba(34, 92, 88, 0.16);
  border-radius: 8px;
  background: #f7faf8;
}

.matrix-map-app b {
  display: block;
  color: #142027;
  font-size: 14px;
}

.matrix-map-app span {
  display: block;
  margin-top: 5px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.5;
}

.beginner-map {
  margin: 18px 0 28px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fbfbf8;
}

.beginner-map-hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(260px, 0.76fr);
  gap: 14px;
  align-items: stretch;
  margin-bottom: 14px;
}

.beginner-map-main {
  padding: 18px 20px;
  border: 1px solid rgba(34, 92, 88, 0.22);
  border-left: 5px solid var(--accent);
  border-radius: 8px;
  background: #ffffff;
}

.beginner-map-main .eyebrow,
.beginner-map-side .eyebrow {
  color: var(--accent);
  font-size: 13px;
  font-weight: 760;
}

.beginner-map-main strong {
  display: block;
  margin-top: 8px;
  color: #142027;
  font-size: 24px;
  line-height: 1.25;
}

.beginner-map-main p {
  margin: 9px 0 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.62;
}

.beginner-map-side {
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #ffffff;
}

.beginner-map-side ol {
  margin: 10px 0 0;
  padding-left: 20px;
}

.beginner-map-side li {
  margin: 7px 0;
  color: #26343d;
  font-size: 14px;
  line-height: 1.45;
}

.beginner-map-route {
  display: grid;
  gap: 12px;
}

.beginner-step {
  display: grid;
  grid-template-columns: 74px minmax(0, 1fr) minmax(210px, 0.56fr);
  gap: 14px;
  align-items: stretch;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #ffffff;
}

.beginner-step-number {
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
  background: #eef4f1;
  color: var(--accent);
  font-size: 24px;
  font-weight: 780;
}

.beginner-step-body h2 {
  margin: 0 0 7px;
  border: 0;
  padding: 0;
  color: #142027;
  font-size: 19px;
}

.beginner-step-body p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.56;
}

.beginner-step-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  margin-top: 10px;
}

.beginner-step-tags span {
  padding: 4px 8px;
  border: 1px solid rgba(34, 92, 88, 0.16);
  border-radius: 999px;
  background: #f8faf8;
  color: #2d4549;
  font-size: 13px;
}

.beginner-step-focus {
  padding: 12px 14px;
  border-radius: 8px;
  background: #f7faf8;
  color: #26343d;
  font-size: 14px;
  line-height: 1.52;
}

.beginner-step-focus b {
  display: block;
  margin-bottom: 4px;
  color: #142027;
}

.beginner-map-chain {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  margin-top: 14px;
  padding: 12px;
  border: 1px dashed rgba(34, 92, 88, 0.26);
  border-radius: 8px;
  background: #ffffff;
}

.beginner-map-chain span {
  padding: 5px 9px;
  border-radius: 6px;
  background: #eef4f1;
  color: #26343d;
  font-size: 13px;
}

.beginner-map-chain .arrow {
  padding: 0;
  background: transparent;
  color: var(--muted);
}

.theorem-box,
.semantic-card {
  --card-accent: #225c58;
  --card-border: rgba(34, 92, 88, 0.24);
  --card-bg: #fbfdfb;
  --card-head-bg: rgba(34, 92, 88, 0.08);
  --card-head-border: rgba(34, 92, 88, 0.16);
  --card-uses-border: rgba(34, 92, 88, 0.22);
  margin: 18px 0;
  overflow: hidden;
  border: 1px solid var(--card-border);
  border-left: 5px solid var(--card-accent);
  border-radius: 8px;
  background: var(--card-bg);
}

.theorem-box.definition,
.semantic-card.definition {
  --card-accent: #2f5f8f;
  --card-border: rgba(47, 95, 143, 0.24);
  --card-bg: #f5f9ff;
  --card-head-bg: rgba(47, 95, 143, 0.08);
  --card-head-border: rgba(47, 95, 143, 0.16);
  --card-uses-border: rgba(47, 95, 143, 0.22);
}

.theorem-box.theorem,
.semantic-card.theorem {
  --card-accent: #8a3d5c;
  --card-border: rgba(138, 61, 92, 0.24);
  --card-bg: #fff7fa;
  --card-head-bg: rgba(138, 61, 92, 0.08);
  --card-head-border: rgba(138, 61, 92, 0.16);
  --card-uses-border: rgba(138, 61, 92, 0.22);
}

.theorem-box.proposition,
.semantic-card.proposition {
  --card-accent: #6f4f91;
  --card-border: rgba(111, 79, 145, 0.24);
  --card-bg: #faf7ff;
  --card-head-bg: rgba(111, 79, 145, 0.08);
  --card-head-border: rgba(111, 79, 145, 0.16);
  --card-uses-border: rgba(111, 79, 145, 0.22);
}

.theorem-box.lemma,
.semantic-card.lemma {
  --card-accent: #9b6b23;
  --card-border: rgba(155, 107, 35, 0.26);
  --card-bg: #fffaf0;
  --card-head-bg: rgba(155, 107, 35, 0.09);
  --card-head-border: rgba(155, 107, 35, 0.17);
  --card-uses-border: rgba(155, 107, 35, 0.24);
}

.theorem-box.corollary,
.semantic-card.corollary {
  --card-accent: #2f755a;
  --card-border: rgba(47, 117, 90, 0.24);
  --card-bg: #f5fbf7;
  --card-head-bg: rgba(47, 117, 90, 0.08);
  --card-head-border: rgba(47, 117, 90, 0.16);
  --card-uses-border: rgba(47, 117, 90, 0.22);
}

.theorem-box.example,
.semantic-card.example {
  --card-accent: #2f6f8a;
  --card-border: rgba(47, 111, 138, 0.24);
  --card-bg: #f4fbfd;
  --card-head-bg: rgba(47, 111, 138, 0.08);
  --card-head-border: rgba(47, 111, 138, 0.16);
  --card-uses-border: rgba(47, 111, 138, 0.22);
}

.theorem-box.proof,
.semantic-card.proof {
  --card-accent: #68737d;
  --card-border: rgba(104, 115, 125, 0.26);
  --card-bg: #f8faf9;
  --card-head-bg: rgba(104, 115, 125, 0.09);
  --card-head-border: rgba(104, 115, 125, 0.18);
  --card-uses-border: rgba(104, 115, 125, 0.24);
}

.theorem-box.exercise,
.semantic-card.exercise {
  --card-accent: #7a5d21;
  --card-border: rgba(122, 93, 33, 0.25);
  --card-bg: #fffaf1;
  --card-head-bg: rgba(122, 93, 33, 0.09);
  --card-head-border: rgba(122, 93, 33, 0.18);
  --card-uses-border: rgba(122, 93, 33, 0.24);
}

.theorem-box.remark,
.semantic-card.remark {
  --card-accent: #5f6872;
  --card-border: rgba(95, 104, 114, 0.25);
  --card-bg: #f8faf9;
  --card-head-bg: rgba(95, 104, 114, 0.08);
  --card-head-border: rgba(95, 104, 114, 0.17);
  --card-uses-border: rgba(95, 104, 114, 0.22);
}

.theorem-head {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 12px;
  align-items: baseline;
  padding: 11px 14px;
  border-bottom: 1px solid var(--card-head-border);
  background: var(--card-head-bg);
}

.proof-status {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 10px;
  align-items: center;
  padding: 8px 14px;
  border-bottom: 1px solid var(--card-head-border);
  background: rgba(255, 255, 255, 0.58);
  color: #52616a;
  font-size: 12.5px;
  line-height: 1.45;
}

.proof-status-label {
  display: inline-flex;
  align-items: center;
  min-height: 22px;
  padding: 2px 8px;
  border: 1px solid rgba(104, 115, 125, 0.28);
  border-radius: 999px;
  background: #ffffff;
  color: #26343d;
  font-weight: 760;
}

.proof-status.complete .proof-status-label {
  border-color: rgba(47, 117, 90, 0.28);
  color: #2f755a;
}

.proof-status.skeleton .proof-status-label {
  border-color: rgba(125, 83, 48, 0.30);
  color: #7d5330;
}

.proof-status.dependent .proof-status-label {
  border-color: rgba(47, 111, 138, 0.30);
  color: #2f6f8a;
}

.proof-status.review .proof-status-label {
  border-color: rgba(133, 61, 68, 0.30);
  color: #853d44;
}

.theorem-kind {
  color: var(--card-accent);
  font-size: 13px;
  font-weight: 780;
}

.theorem-title {
  color: #142027;
  font-size: 16px;
  font-weight: 720;
}

.theorem-body {
  padding: 13px 16px 15px;
}

.theorem-body p:first-child {
  margin-top: 0;
}

.theorem-body p:last-child {
  margin-bottom: 0;
}

.global-tip {
  margin: 11px 0 9px;
  padding: 8px 10px;
  border: 1px solid rgba(38, 52, 61, 0.13);
  border-left: 3px solid var(--card-uses-border);
  border-radius: 7px;
  background: rgba(255, 255, 255, 0.72);
  color: #52616a;
  font-size: 13px;
  line-height: 1.55;
}

.global-tip strong {
  margin-right: 4px;
  color: #26343d;
  font-weight: 760;
}

.theorem-box.theorem .global-tip,
.semantic-card.theorem .global-tip {
  border-color: rgba(138, 61, 92, 0.14);
  border-left-color: rgba(138, 61, 92, 0.34);
}

.theorem-box.lemma .global-tip,
.semantic-card.lemma .global-tip {
  border-color: rgba(155, 107, 35, 0.15);
  border-left-color: rgba(155, 107, 35, 0.34);
}

.theorem-box.corollary .global-tip,
.semantic-card.corollary .global-tip {
  border-color: rgba(47, 117, 90, 0.14);
  border-left-color: rgba(47, 117, 90, 0.34);
}

.theorem-box.example .global-tip,
.semantic-card.example .global-tip {
  border-color: rgba(47, 111, 138, 0.14);
  border-left-color: rgba(47, 111, 138, 0.34);
}

.theorem-box.exercise .global-tip,
.semantic-card.exercise .global-tip {
  border-color: rgba(122, 93, 33, 0.15);
  border-left-color: rgba(122, 93, 33, 0.34);
}

.theorem-box.proof .global-tip,
.semantic-card.proof .global-tip,
.theorem-box.remark .global-tip,
.semantic-card.remark .global-tip {
  border-color: rgba(104, 115, 125, 0.16);
  border-left-color: rgba(104, 115, 125, 0.34);
}

.content mjx-container[display="true"],
.paired-pane-scroll mjx-container[display="true"],
.formula-container {
  display: block;
  width: 100%;
  overflow: visible;
  margin: 14px 0;
  padding: 13px 18px;
  border: 1px solid var(--card-head-border);
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.64);
  text-align: center;
}

.content mjx-container[jax="SVG"][display="true"] > svg,
.paired-pane-scroll mjx-container[jax="SVG"][display="true"] > svg,
.formula-container mjx-container[jax="SVG"] > svg {
  max-width: 100%;
  height: auto;
  overflow: visible;
}

.theorem-body mjx-container[display="true"] {
  width: calc(100% + 12px);
  margin-left: -6px;
  margin-right: -6px;
}

.formula-container {
  text-align: center;
}

.theorem-uses {
  margin-top: 12px;
  padding-top: 10px;
  border-top: 1px dashed var(--card-uses-border);
  color: var(--muted);
  font-size: 14px;
}

img {
  max-width: 100%;
  height: auto;
  border-radius: 6px;
}

.book-figure {
  margin: 20px 0 24px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fbfbf8;
}

.book-figure img {
  display: block;
  max-height: 520px;
  margin: 0 auto;
  object-fit: contain;
}

.book-figure figcaption {
  margin-top: 10px;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.5;
  text-align: center;
}

.book-figure-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  align-items: end;
}

.book-figure-grid img {
  max-height: 360px;
}

.math.display {
  overflow: visible;
  padding: 0;
}

.footer {
  margin-top: 42px;
  color: var(--muted);
  font-size: 13px;
}

.paired-reading-shell {
  min-width: 0;
  padding: 24px 28px 42px;
}

.paired-reader-header {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  align-items: center;
  justify-content: space-between;
  margin: 0 0 16px;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: var(--shadow);
}

.paired-reader-title {
  color: #142027;
  font-size: 20px;
  font-weight: 760;
  line-height: 1.3;
}

.paired-reader-subtitle {
  margin-top: 3px;
  color: var(--muted);
  font-size: 13px;
}

.paired-reader-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: flex-start;
}

.paired-toc-menu {
  position: relative;
}

.paired-toc-summary {
  cursor: pointer;
  list-style: none;
}

.paired-toc-summary::-webkit-details-marker {
  display: none;
}

.paired-toc-summary::after {
  content: "▾";
  margin-left: 8px;
  color: rgba(34, 92, 88, 0.78);
  font-size: 12px;
}

.paired-toc-menu[open] .paired-toc-summary {
  border-color: rgba(34, 92, 88, 0.52);
  background: #e4efeb;
}

.paired-toc-menu[open] .paired-toc-summary::after {
  content: "▴";
}

.paired-toc-panel {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  z-index: 20;
  width: min(380px, calc(100vw - 42px));
  max-height: min(70vh, 560px);
  overflow: auto;
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #ffffff;
  box-shadow: 0 18px 40px rgba(28, 38, 45, 0.16);
}

.paired-toc-title {
  padding: 4px 7px 8px;
  color: #142027;
  font-size: 13px;
  font-weight: 760;
}

.paired-toc-list {
  display: grid;
  gap: 2px;
}

.paired-toc-link {
  display: block;
  padding: 7px 8px;
  border-radius: 6px;
  color: #283940;
  font-size: 13px;
  line-height: 1.35;
}

.paired-toc-link:hover {
  background: #eef4f1;
  color: var(--accent);
}

.paired-toc-level-2 {
  padding-left: 22px;
  color: #52636a;
  font-size: 12.5px;
}

.paired-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 18px;
  align-items: start;
}

.paired-pane {
  min-width: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: var(--shadow);
}

.paired-pane[data-paired-pane="note"] {
  display: grid;
  grid-template-rows: auto minmax(0, 1fr);
}

.paired-pane-head {
  position: sticky;
  top: 0;
  z-index: 2;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 11px 16px;
  border-bottom: 1px solid var(--line);
  background: #f9faf8;
}

.paired-pane-heading {
  display: flex;
  min-width: 0;
  align-items: baseline;
  gap: 10px;
}

.paired-pane-kicker {
  flex: 0 0 auto;
  color: var(--accent);
  font-size: 13px;
  font-weight: 760;
}

.paired-pane-title {
  min-width: 0;
  overflow: hidden;
  color: #142027;
  font-size: 15px;
  font-weight: 720;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.paired-note-stage {
  min-width: 0;
  min-height: 0;
}

.paired-note-stage > .paired-pane-scroll {
  height: calc(100vh - 162px);
}

.paired-aux-actions {
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  gap: 6px;
}

.paired-aux-actions[hidden],
.paired-aux-view[hidden],
.paired-pane-scroll[hidden] {
  display: none !important;
}

.paired-aux-open,
.paired-aux-return {
  display: inline-flex;
  min-height: 32px;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--line);
  border-radius: 5px;
  background: var(--control-bg);
  color: var(--accent);
  cursor: pointer;
  font: inherit;
  font-size: 12.5px;
  font-weight: 730;
  text-decoration: none;
  touch-action: manipulation;
}

.paired-aux-open {
  width: 32px;
  padding: 0;
  font-size: 17px;
}

.paired-aux-return {
  gap: 5px;
  padding: 5px 9px;
}

.paired-aux-open:hover,
.paired-aux-return:hover,
.paired-aux-open:focus-visible,
.paired-aux-return:focus-visible {
  border-color: color-mix(in srgb, var(--accent) 44%, var(--line));
  outline: none;
  background: var(--control-hover);
}

.paired-aux-view {
  position: relative;
  height: calc(100vh - 162px);
  min-height: 0;
  overflow: hidden;
  background: var(--panel);
}

.paired-aux-frame {
  display: block;
  width: 100%;
  height: 100%;
  border: 0;
  background: var(--panel);
}

.paired-aux-loading {
  position: absolute;
  inset: 0;
  z-index: 1;
  display: grid;
  place-items: center;
  padding: 24px;
  background: var(--panel);
  color: var(--muted);
  font-size: 13px;
  font-weight: 700;
  text-align: center;
}

.paired-aux-view.is-loaded .paired-aux-loading {
  display: none;
}

.paired-page.paired-aux-active .back-to-top {
  display: none;
}

.paired-pane-scroll {
  height: calc(100vh - 168px);
  overflow: auto;
  padding: 26px 30px 40px;
}

.paired-pane-scroll .page-title {
  font-size: 24px;
}

.paired-pane-scroll h1 {
  font-size: 24px;
}

.paired-pane-scroll h2 {
  font-size: 20px;
}

@media (max-width: 980px) {
  .layout { grid-template-columns: 1fr; }
  .sidebar {
    position: relative;
    height: auto;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }
  .content-shell,
  .content-shell.has-page-toc {
    display: block;
    padding: 22px 16px 56px;
  }
  .content {
    padding: 24px 20px;
  }
  .content,
  .paired-pane-scroll {
    max-width: 100%;
    overflow-x: hidden;
  }
  .content table,
  .paired-pane-scroll table {
    display: block;
    max-width: 100%;
    overflow-x: auto;
  }
  .content mjx-container[display="true"],
  .paired-pane-scroll mjx-container[display="true"],
  .formula-container {
    padding: 11px 12px;
    overflow-x: auto;
    overflow-y: hidden;
  }
  .theorem-body mjx-container[display="true"] {
    width: 100%;
    margin-left: 0;
    margin-right: 0;
  }
  .concept-grid {
    grid-template-columns: 1fr;
  }
  .concept-card {
    min-height: 0;
  }
  .matrix-map-core,
  .matrix-map-thesis,
  .matrix-map-flow,
  .matrix-map-apps {
    grid-template-columns: 1fr;
  }
  .matrix-map-stage {
    min-height: 0;
  }
  .matrix-map-stage::after {
    display: none;
  }
  .beginner-map-hero,
  .beginner-step {
    grid-template-columns: 1fr;
  }
  .beginner-step-number {
    width: 52px;
    height: 42px;
  }
  .book-figure-grid {
    grid-template-columns: 1fr;
  }
  .toc-sidebar { display: none; }
  .page-title { font-size: 25px; }
  h1 { font-size: 24px; }
  h2 { font-size: 20px; }
  .paired-reading-shell {
    padding: 18px 14px 42px;
  }
  .layout.paired-layout {
    display: block;
  }
  .paired-layout .sidebar {
    display: none;
  }
  .paired-toc-panel {
    position: fixed;
    top: 146px;
    left: 14px;
    right: 14px;
    width: auto;
    max-height: calc(100vh - 168px);
  }
  .paired-grid {
    grid-template-columns: 1fr;
  }
  .paired-pane-scroll {
    height: auto;
    max-height: none;
  }
}

/* Framework 2.0: responsive reading shell and reader controls. */
:root {
  --sidebar-width: 264px;
  --reader-measure: 800px;
  --reader-font-size: 16px;
  --reader-line-height: 1.78;
  --topbar-height: 58px;
  --control-bg: #f1f5f2;
  --control-hover: #e6efea;
  --focus: #b8682d;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 78px;
}

html[data-font-scale="small"] { --reader-font-size: 15px; }
html[data-font-scale="large"] { --reader-font-size: 17px; }
html[data-font-scale="xlarge"] { --reader-font-size: 18px; }
html[data-reader-width="narrow"] { --reader-measure: 700px; }
html[data-reader-width="wide"] { --reader-measure: 920px; }
html[data-line-height="compact"] { --reader-line-height: 1.62; }
html[data-line-height="relaxed"] { --reader-line-height: 1.9; }

html[data-theme="dark"] {
  color-scheme: dark;
  --bg: #181c1d;
  --panel: #202526;
  --ink: #e8ece9;
  --muted: #aab4b0;
  --line: #3a4541;
  --accent: #78b9ad;
  --accent-2: #d29a67;
  --code-bg: #29312f;
  --sidebar: #1d2322;
  --reference-glass-tint: #29423d;
  --reference-glass-highlight: #d8e9e3;
  --control-bg: #293330;
  --control-hover: #33413d;
  --shadow: 0 12px 30px rgba(0, 0, 0, 0.2);
}

[hidden] { display: none !important; }

body {
  background: var(--panel);
  font-size: var(--reader-font-size);
  line-height: var(--reader-line-height);
}

button,
input,
select { font: inherit; }

button { color: inherit; }

a:focus-visible,
button:focus-visible,
summary:focus-visible,
input:focus-visible,
select:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--focus) 72%, transparent);
  outline-offset: 3px;
}

.skip-link {
  position: fixed;
  top: 8px;
  left: 12px;
  z-index: 200;
  padding: 8px 12px;
  border: 1px solid var(--focus);
  border-radius: 6px;
  background: var(--panel);
  color: var(--ink);
  transform: translateY(-150%);
}

.skip-link:focus { transform: translateY(0); }

.reading-progress {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 190;
  width: 100%;
  height: 3px;
  pointer-events: none;
}

.reading-progress-bar {
  width: 100%;
  height: 100%;
  background: var(--accent-2);
  transform: scaleX(0);
  transform-origin: left center;
}

.site-topbar {
  display: none;
  position: sticky;
  top: 0;
  z-index: 70;
  min-height: var(--topbar-height);
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 8px 16px;
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--panel) 94%, transparent);
  backdrop-filter: blur(12px);
}

.topbar-brand {
  flex: 1 1 auto;
  min-width: 0;
  border: 0;
  color: var(--ink);
  font-size: 15px;
  font-weight: 760;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.topbar-actions {
  display: flex;
  flex: 0 0 auto;
  gap: 8px;
}

.topbar-button,
.sidebar-close,
.search-close,
.back-to-top,
.reader-step-button {
  display: inline-grid;
  min-width: 38px;
  min-height: 38px;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--control-bg);
  cursor: pointer;
}

.topbar-button:hover,
.sidebar-close:hover,
.search-close:hover,
.back-to-top:hover,
.reader-step-button:hover { background: var(--control-hover); }

.layout {
  grid-template-columns: var(--sidebar-width) minmax(0, 1fr);
  background: var(--panel);
}

.sidebar {
  z-index: 80;
  width: var(--sidebar-width);
  padding: 20px 16px 28px;
  background: var(--sidebar);
}

.sidebar-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 18px;
}

.brand-link {
  border: 0;
  color: #142027;
  font-size: 17px;
  font-weight: 780;
  line-height: 1.32;
}

html[data-theme="dark"] .brand-link { color: var(--ink); }

.sidebar-close { display: none; }

.sidebar-tools {
  display: grid;
  grid-template-columns: 1fr;
  gap: 8px;
  margin-bottom: 18px;
}

.sidebar-tool-button {
  display: inline-flex;
  min-height: 38px;
  align-items: center;
  justify-content: center;
  padding: 7px 10px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--control-bg);
  color: var(--ink);
  cursor: pointer;
  font-size: 13px;
  font-weight: 720;
}

.nav-section {
  margin: 18px 0;
}

.nav-section h2,
.nav-group > summary {
  margin: 0 0 7px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 760;
  line-height: 1.4;
}

.nav-group > summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 32px;
  padding: 5px 7px;
  border-radius: 6px;
  cursor: pointer;
  list-style: none;
}

.nav-group > summary::-webkit-details-marker { display: none; }
.nav-group > summary::after { content: "+"; font-size: 16px; }
.nav-group[open] > summary::after { content: "−"; }
.nav-group > summary:hover { background: color-mix(in srgb, var(--accent) 8%, transparent); }

.nav-link {
  display: block;
  min-height: 32px;
  padding: 6px 8px;
  border: 0;
  border-radius: 6px;
  color: var(--ink);
  font-size: 13.5px;
  line-height: 1.4;
}

.nav-link:hover,
.nav-link.active {
  background: color-mix(in srgb, var(--accent) 12%, transparent);
  color: var(--accent);
}

.chapter-list { display: grid; gap: 3px; }

.chapter-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 6px;
  align-items: center;
  min-height: 36px;
  padding: 3px 4px 3px 7px;
  border-radius: 6px;
}

.chapter-row.active { background: color-mix(in srgb, var(--accent) 10%, transparent); }

.chapter-main {
  min-width: 0;
  border: 0;
  color: var(--ink);
  font-size: 13px;
  line-height: 1.35;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.chapter-row.active .chapter-main { color: var(--accent); font-weight: 730; }

.chapter-modes {
  display: inline-flex;
  gap: 2px;
}

.chapter-mode-link {
  display: inline-grid;
  width: 27px;
  height: 27px;
  place-items: center;
  border: 0;
  border-radius: 5px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 760;
}

.chapter-mode-link:hover,
.chapter-mode-link.active {
  background: var(--panel);
  color: var(--accent);
}

.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 75;
  background: rgba(20, 28, 30, 0.42);
}

.content-shell {
  min-height: 100vh;
  padding: 34px 42px 80px;
  background: var(--panel);
}

.content-shell.has-page-toc {
  grid-template-columns: minmax(0, var(--reader-measure)) 248px;
  justify-content: center;
  gap: 30px;
}

.content,
.content-shell.has-page-toc .content {
  width: 100%;
  max-width: var(--reader-measure);
  margin: 0 auto;
  padding: 18px 10px 76px;
  border: 0;
  border-radius: 0;
  background: transparent;
  box-shadow: none;
  font-size: var(--reader-font-size);
  line-height: var(--reader-line-height);
}

.page-title {
  margin: 0 0 14px;
  padding: 0;
  border: 0;
  color: var(--ink);
  font-size: 30px;
  line-height: 1.3;
}

.reader-toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 9px;
  align-items: center;
  justify-content: space-between;
  margin: 0 0 28px;
  padding: 10px 0 16px;
  border-bottom: 1px solid var(--line);
}

.reader-toolbar-utility { justify-content: flex-end; }

.mode-switch {
  display: inline-flex;
  min-height: 38px;
  padding: 3px;
  border: 1px solid var(--line);
  border-radius: 7px;
  background: var(--control-bg);
}

.mode-switch a {
  display: inline-flex;
  align-items: center;
  padding: 5px 10px;
  border: 0;
  border-radius: 5px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 720;
}

.mode-switch a.active {
  background: var(--panel);
  color: var(--accent);
  box-shadow: 0 1px 4px rgba(20, 35, 38, 0.1);
}

.reader-toolbar-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
}

.inline-page-toc { display: none; position: relative; }

.reader-settings,
.inline-page-toc { position: relative; }

.reader-settings > summary,
.inline-page-toc > summary {
  cursor: pointer;
  list-style: none;
}

.reader-settings > summary::-webkit-details-marker,
.inline-page-toc > summary::-webkit-details-marker { display: none; }

.reader-popover,
.inline-toc-panel {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  z-index: 45;
  width: min(340px, calc(100vw - 32px));
  max-height: min(68vh, 560px);
  overflow: auto;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: var(--shadow);
}

.reader-setting-row {
  display: grid;
  grid-template-columns: 92px minmax(0, 1fr);
  gap: 10px;
  align-items: center;
  padding: 7px 0;
  color: var(--muted);
  font-size: 13px;
}

.reader-setting-control {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 7px;
}

.reader-setting-control select {
  width: 100%;
  min-height: 36px;
  padding: 5px 8px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--panel);
  color: var(--ink);
}

.reader-step-button { min-width: 34px; min-height: 34px; }
.reader-font-value { min-width: 42px; text-align: center; color: var(--ink); }

.toc-sidebar { width: 248px; }
.page-toc { background: color-mix(in srgb, var(--sidebar) 55%, var(--panel)); }
.page-toc a.active { color: var(--accent-2); font-weight: 750; }
.page-toc a[aria-current="location"] { color: var(--accent-2); }

.anchor-alias {
  position: relative;
  top: -76px;
  visibility: hidden;
}

.chapter-pager {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 54px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
}

.chapter-pager-link {
  display: grid;
  gap: 2px;
  min-height: 64px;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--ink);
}

.chapter-pager-link.next { text-align: right; }
.chapter-pager-direction { color: var(--muted); font-size: 12px; }
.chapter-pager-title { color: var(--accent); font-size: 14px; font-weight: 730; }

.learning-checklist-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin: 16px 0 8px;
  padding: 0 2px;
}

.learning-checklist-progress {
  display: flex;
  min-width: 0;
  flex: 1 1 auto;
  align-items: center;
  gap: 12px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 680;
}

.learning-checklist-progress-track {
  width: min(220px, 32vw);
  height: 6px;
  overflow: hidden;
  border-radius: 999px;
  background: color-mix(in srgb, var(--line) 72%, transparent);
}

.learning-checklist-progress-fill {
  display: block;
  width: var(--checklist-progress, 0%);
  height: 100%;
  border-radius: inherit;
  background: var(--accent);
  transition: width 160ms ease;
}

.learning-checklist-reset {
  min-height: 34px;
  padding: 5px 10px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--control-bg);
  color: var(--muted);
  cursor: pointer;
  font-size: 13px;
  font-weight: 680;
}

.learning-checklist-reset:hover {
  background: var(--control-hover);
  color: var(--ink);
}

ul.learning-checklist {
  margin: 0 0 30px;
  padding: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: color-mix(in srgb, var(--panel) 96%, var(--sidebar));
  list-style: none;
}

ul.learning-checklist > li {
  margin: 0;
  border-bottom: 1px solid var(--line);
}

ul.learning-checklist > li:last-child { border-bottom: 0; }

.learning-checklist-label {
  display: grid;
  grid-template-columns: 20px minmax(0, 1fr);
  gap: 11px;
  align-items: start;
  min-height: 48px;
  padding: 10px 14px;
  cursor: pointer;
}

.learning-checklist-label:hover {
  background: color-mix(in srgb, var(--accent) 5%, transparent);
}

.learning-checklist input[type="checkbox"],
.learning-checklist-table input[type="checkbox"] {
  width: 17px;
  height: 17px;
  margin: 5px 0 0;
  accent-color: var(--accent);
  cursor: pointer;
}

.learning-checklist-text {
  min-width: 0;
  line-height: 1.68;
}

ul.learning-checklist > li.is-complete,
.learning-checklist-table tr.is-complete td {
  background: color-mix(in srgb, var(--accent) 5%, var(--panel));
}

ul.learning-checklist > li.is-complete .learning-checklist-text,
.learning-checklist-table tr.is-complete td:not(.study-check-control) {
  color: var(--muted);
}

table.learning-checklist-table {
  margin: 0 0 30px;
  border-collapse: separate;
  border-spacing: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 8px;
}

.learning-checklist-table th,
.learning-checklist-table td { border-width: 0 0 1px 1px; }
.learning-checklist-table th:first-child,
.learning-checklist-table td:first-child { border-left: 0; }
.learning-checklist-table tbody tr:last-child td { border-bottom: 0; }
.learning-checklist-table .study-check-control {
  width: 56px;
  padding: 8px;
  text-align: center;
  vertical-align: middle;
}
.learning-checklist-table th.study-check-control {
  color: var(--muted);
  font-size: 12px;
}
.learning-checklist-table input[type="checkbox"] { margin-top: 0; }

.footer { display: none; }

.home-reader-entry {
  margin: 4px 0 34px;
  padding: 18px 0 28px;
  border-bottom: 1px solid var(--line);
}

.continue-reading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 20px;
  padding: 14px 16px;
  border: 1px solid color-mix(in srgb, var(--accent) 34%, var(--line));
  border-radius: 8px;
  background: color-mix(in srgb, var(--accent) 6%, var(--panel));
}

.continue-reading-title { font-weight: 760; }
.continue-reading-meta { color: var(--muted); font-size: 13px; }

.home-chapter-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.home-chapter-item {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 10px;
  align-items: center;
  min-height: 58px;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
}

.home-chapter-title { color: var(--ink); font-size: 14px; font-weight: 730; }
.home-chapter-modes { display: inline-flex; gap: 5px; }
.home-chapter-modes a { border: 0; color: var(--accent); font-size: 12px; }

.search-overlay {
  position: fixed;
  top: var(--search-viewport-top, 0px);
  right: 0;
  bottom: auto;
  left: 0;
  z-index: 160;
  display: grid;
  height: 100vh;
  height: var(--search-viewport-height, 100vh);
  place-items: start center;
  padding: min(12vh, 100px) 16px 24px;
  background: rgba(17, 25, 27, 0.52);
  overscroll-behavior: contain;
}

.search-panel {
  width: min(720px, 100%);
  max-height: min(76vh, 720px);
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: 0 24px 60px rgba(12, 20, 22, 0.25);
}

.search-head {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto auto;
  gap: 10px;
  padding: 14px;
  border-bottom: 1px solid var(--line);
}

.search-input {
  min-width: 0;
  width: 100%;
  min-height: 42px;
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  appearance: none;
  background: var(--panel);
  color: var(--ink);
  font: inherit;
  font-size: 16px;
  line-height: 1.4;
  touch-action: manipulation;
  -webkit-appearance: none;
}

.search-submit {
  min-width: 58px;
  min-height: 42px;
  padding: 8px 12px;
  border: 1px solid color-mix(in srgb, var(--accent) 42%, var(--line));
  border-radius: 6px;
  background: color-mix(in srgb, var(--accent) 9%, var(--panel));
  color: var(--accent);
  cursor: pointer;
  font: inherit;
  font-size: 14px;
  font-weight: 740;
  touch-action: manipulation;
}

.search-submit:hover { background: color-mix(in srgb, var(--accent) 14%, var(--panel)); }

.search-status { padding: 10px 16px 0; color: var(--muted); font-size: 13px; }
.search-results { max-height: calc(min(76vh, 720px) - 112px); overflow: auto; padding: 8px 10px 14px; -webkit-overflow-scrolling: touch; }
.search-result { display: block; padding: 10px 8px; border: 0; border-radius: 6px; }
.search-result:hover { background: var(--control-bg); }
.search-result-title { color: var(--ink); font-weight: 740; }
.search-result-meta { margin-top: 2px; color: var(--muted); font-size: 12px; }
.search-result-snippet { margin-top: 4px; color: var(--muted); font-size: 13px; line-height: 1.55; }

.semantic-copy-popover {
  position: fixed;
  z-index: 185;
  display: flex;
  max-width: calc(100vw - 16px);
  min-height: 42px;
  align-items: center;
  gap: 2px;
  padding: 4px;
  border: 1px solid color-mix(in srgb, var(--line) 76%, transparent);
  border-radius: 7px;
  background: color-mix(in srgb, var(--panel) 88%, transparent);
  box-shadow:
    inset 0 1px 0 color-mix(in srgb, #ffffff 64%, transparent),
    0 12px 32px rgba(12, 20, 22, 0.18);
  color: var(--ink);
  -webkit-backdrop-filter: blur(18px) saturate(1.12);
  backdrop-filter: blur(18px) saturate(1.12);
}

.semantic-copy-button {
  display: inline-flex;
  min-height: 34px;
  align-items: center;
  gap: 7px;
  padding: 6px 9px;
  border: 0;
  border-radius: 5px;
  background: transparent;
  color: var(--accent);
  cursor: pointer;
  font: inherit;
  font-size: 13px;
  font-weight: 740;
  touch-action: manipulation;
}

.semantic-copy-button:hover,
.semantic-copy-button:focus-visible {
  outline: none;
  background: color-mix(in srgb, var(--accent) 9%, transparent);
}

.semantic-copy-icon {
  position: relative;
  display: inline-block;
  width: 15px;
  height: 15px;
  flex: 0 0 auto;
}

.semantic-copy-icon::before,
.semantic-copy-icon::after {
  content: "";
  position: absolute;
  width: 9px;
  height: 10px;
  border: 1.5px solid currentColor;
  border-radius: 2px;
}

.semantic-copy-icon::before { top: 1px; left: 1px; opacity: 0.56; }
.semantic-copy-icon::after { right: 1px; bottom: 1px; background: inherit; }

.semantic-copy-status {
  min-height: 24px;
  align-items: center;
  padding: 3px 7px;
  border-left: 1px solid var(--line);
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
  white-space: nowrap;
}

.semantic-copy-status:not(:empty) { display: inline-flex; }
.semantic-copy-status:empty { display: none; }
.semantic-copy-popover[data-state="success"] .semantic-copy-status { color: #2f755a; }
.semantic-copy-popover[data-state="error"] .semantic-copy-status { color: #9b3f3f; }

@media (max-width: 820px), (any-pointer: coarse) {
  .semantic-copy-popover { min-height: 52px; }
  .semantic-copy-button {
    min-height: 44px;
    padding: 8px 11px;
    font-size: 14px;
  }
}

.reference-overlay {
  position: fixed;
  top: var(--reference-viewport-top, 0px);
  right: 0;
  bottom: auto;
  left: 0;
  z-index: 170;
  display: flex;
  height: 100vh;
  height: var(--reference-viewport-height, 100vh);
  justify-content: flex-end;
  background: rgba(17, 25, 27, 0.48);
  overscroll-behavior: contain;
}

.reference-panel {
  display: grid;
  grid-template-rows: auto auto auto minmax(0, 1fr);
  width: min(560px, calc(100% - 36px));
  height: 100%;
  min-height: 0;
  overflow: hidden;
  border-left: 1px solid var(--line);
  background: var(--panel);
  box-shadow: -18px 0 48px rgba(12, 20, 22, 0.2);
}

.reference-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 18px 20px 12px;
}

.reference-eyebrow {
  color: var(--accent);
  font-size: 12px;
  font-weight: 760;
}

.reference-heading {
  margin-top: 1px;
  color: var(--ink);
  font-size: 21px;
  font-weight: 780;
}

.reference-icon-button,
.reference-pin,
.reference-mini-button {
  display: inline-grid;
  width: 38px;
  height: 38px;
  flex: 0 0 auto;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--control-bg);
  color: var(--ink);
  cursor: pointer;
  font-size: 20px;
}

.reference-icon-button:hover,
.reference-pin:hover,
.reference-mini-button:hover { background: var(--control-hover); }

.reference-search-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 8px;
  padding: 0 20px 12px;
}

.reference-input {
  min-width: 0;
  width: 100%;
  min-height: 44px;
  padding: 9px 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  appearance: none;
  background: var(--panel);
  color: var(--ink);
  font: inherit;
  font-size: 16px;
  line-height: 1.4;
  touch-action: manipulation;
  -webkit-appearance: none;
}

.reference-search-submit {
  min-width: 58px;
  min-height: 44px;
  padding: 8px 12px;
  border: 1px solid color-mix(in srgb, var(--accent) 42%, var(--line));
  border-radius: 6px;
  background: color-mix(in srgb, var(--accent) 9%, var(--panel));
  color: var(--accent);
  cursor: pointer;
  font: inherit;
  font-size: 14px;
  font-weight: 740;
  touch-action: manipulation;
}

.reference-search-submit:hover { background: color-mix(in srgb, var(--accent) 14%, var(--panel)); }

.reference-filters {
  display: flex;
  gap: 4px;
  overflow-x: auto;
  padding: 0 20px 12px;
  border-bottom: 1px solid var(--line);
  scrollbar-width: thin;
}

.reference-filter {
  min-height: 32px;
  flex: 0 0 auto;
  padding: 5px 10px;
  border: 0;
  border-radius: 5px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font-size: 13px;
  font-weight: 700;
  touch-action: manipulation;
}

.reference-filter:hover { background: var(--control-bg); color: var(--ink); }
.reference-filter.active { background: var(--control-bg); color: var(--accent); }

.reference-browse {
  min-height: 0;
  overflow-y: auto;
  overscroll-behavior: contain;
  -webkit-overflow-scrolling: touch;
}

.reference-status {
  padding: 12px 20px 8px;
  color: var(--muted);
  font-size: 13px;
}

.reference-results { padding: 0 10px 24px; }

.reference-group-label {
  padding: 13px 10px 5px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 760;
}

.reference-result {
  display: grid;
  width: 100%;
  gap: 5px;
  padding: 11px 10px 12px;
  border: 0;
  border-bottom: 1px solid var(--line);
  border-radius: 0;
  background: transparent;
  color: var(--ink);
  cursor: pointer;
  text-align: left;
  touch-action: manipulation;
}

.reference-result:hover,
.reference-result:focus-visible { background: color-mix(in srgb, var(--accent) 6%, transparent); }

.reference-result-head {
  display: flex;
  min-width: 0;
  align-items: baseline;
  gap: 8px;
}

.reference-result-kind,
.reference-kind {
  flex: 0 0 auto;
  color: var(--accent);
  font-size: 12px;
  font-weight: 760;
}

.reference-result-title {
  min-width: 0;
  color: var(--ink);
  font-size: 15px;
  font-weight: 750;
  line-height: 1.45;
}

.reference-result-meta,
.reference-chapter { color: var(--muted); font-size: 12px; }

.reference-result-summary {
  display: -webkit-box;
  overflow: hidden;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.55;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
}

.reference-empty {
  padding: 36px 18px;
  color: var(--muted);
  text-align: center;
}

.reference-preview {
  display: flex;
  min-height: 0;
  overflow: hidden;
  flex-direction: column;
  outline: none;
}

.reference-preview-toolbar {
  position: relative;
  z-index: 2;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 20px 10px;
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--panel) 94%, transparent);
  backdrop-filter: blur(8px);
}

.reference-back {
  min-height: 34px;
  padding: 5px 9px;
  border: 0;
  border-radius: 5px;
  background: var(--control-bg);
  color: var(--accent);
  cursor: pointer;
  font-size: 13px;
  font-weight: 720;
}

.reference-float-caption {
  display: none;
  min-width: 0;
  overflow: hidden;
  color: var(--ink);
  font-size: 13px;
  font-weight: 730;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.reference-preview-controls {
  display: flex;
  flex: 0 0 auto;
  align-items: center;
  gap: 6px;
}

.reference-pin,
.reference-mini-button { width: 34px; height: 34px; font-size: 18px; }

.reference-preview-content {
  min-height: 0;
  overflow-y: auto;
  overscroll-behavior: contain;
  padding: 0 20px 30px;
  -webkit-overflow-scrolling: touch;
}

.reference-preview-meta {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-top: 18px;
}

.reference-preview-title {
  margin: 8px 0 16px;
  padding: 0 0 10px;
  border-bottom: 1px solid var(--line);
  font-size: 23px;
  letter-spacing: 0;
}

.reference-statement {
  color: var(--ink);
  font-size: 15px;
  line-height: 1.75;
}

.reference-statement > :first-child { margin-top: 0; }
.reference-statement > :last-child { margin-bottom: 0; }

.reference-statement mjx-container[display="true"] {
  display: block;
  width: 100%;
  max-width: 100%;
  overflow: visible;
  margin: 13px 0;
  padding: 12px 8px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: color-mix(in srgb, var(--sidebar) 45%, var(--panel));
  text-align: center;
}

.reference-statement mjx-container[jax="SVG"][display="true"] > svg {
  max-width: 100%;
  height: auto;
}

.reference-statement mjx-container[display="true"][style*="min-width"],
.reference-statement mjx-container[jax="SVG"][display="true"] > svg[style*="min-width"] {
  min-width: 0 !important;
}

.reference-purpose {
  margin-top: 18px;
  padding: 10px 12px;
  border-left: 3px solid color-mix(in srgb, var(--accent) 62%, var(--line));
  border-radius: 0 6px 6px 0;
  background: color-mix(in srgb, var(--accent) 6%, var(--panel));
  color: var(--muted);
  font-size: 13px;
  line-height: 1.62;
}

.reference-purpose::before {
  content: "作用";
  display: block;
  margin-bottom: 3px;
  color: var(--accent);
  font-size: 12px;
  font-weight: 760;
}

.reference-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 20px;
}

.reference-action {
  display: inline-flex;
  min-height: 36px;
  align-items: center;
  justify-content: center;
  padding: 6px 11px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--control-bg);
  color: var(--accent);
  font-size: 13px;
  font-weight: 720;
}

.reference-action.primary {
  border-color: color-mix(in srgb, var(--accent) 45%, var(--line));
  background: color-mix(in srgb, var(--accent) 10%, var(--panel));
}

.reference-overlay.reference-peek-mode {
  background: transparent;
  pointer-events: none;
}

.reference-peek-mode .reference-panel {
  position: fixed;
  top: 72px;
  right: 18px;
  bottom: auto;
  left: auto;
  display: block;
  width: min(460px, calc(100vw - 32px));
  height: min(640px, calc(100vh - 32px));
  min-width: 340px;
  min-height: 260px;
  padding: 4px;
  overflow: visible;
  border: 1px solid color-mix(
    in srgb,
    var(--reference-glass-highlight) 64%,
    var(--line)
  );
  border-radius: 8px;
  background: linear-gradient(
    145deg,
    color-mix(in srgb, var(--reference-glass-highlight) 38%, transparent),
    color-mix(in srgb, var(--reference-glass-tint) 68%, transparent)
  );
  box-shadow:
    inset 0 1px 0 color-mix(in srgb, var(--reference-glass-highlight) 72%, transparent),
    0 0 0 1px color-mix(in srgb, var(--reference-glass-tint) 18%, transparent),
    0 18px 52px rgba(12, 20, 22, 0.18),
    0 6px 18px rgba(12, 20, 22, 0.1);
  pointer-events: auto;
  -webkit-backdrop-filter: blur(24px) saturate(1.16);
  backdrop-filter: blur(24px) saturate(1.16);
}

.reference-peek-mode .reference-head,
.reference-peek-mode .reference-search-row,
.reference-peek-mode .reference-filters,
.reference-peek-mode .reference-browse { display: none; }

.reference-peek-mode .reference-preview {
  position: relative;
  height: 100%;
  overflow: hidden;
  border-radius: 6px;
  background: color-mix(in srgb, var(--panel) 96%, transparent);
  box-shadow: inset 0 0 0 1px color-mix(
    in srgb,
    var(--reference-glass-highlight) 52%,
    transparent
  );
}

.reference-peek-mode .reference-preview-toolbar {
  flex: 0 0 auto;
  padding: 8px 10px;
  cursor: grab;
  touch-action: none;
  user-select: none;
  background: linear-gradient(
    to bottom,
    color-mix(in srgb, var(--reference-glass-highlight) 78%, transparent),
    color-mix(in srgb, var(--reference-glass-tint) 72%, transparent)
  );
  box-shadow: 0 8px 18px color-mix(in srgb, var(--reference-glass-tint) 16%, transparent);
  -webkit-backdrop-filter: blur(18px) saturate(1.12);
  backdrop-filter: blur(18px) saturate(1.12);
}

.reference-peek-mode.reference-dragging .reference-preview-toolbar { cursor: grabbing; }
.reference-peek-mode.reference-resizing .reference-panel {
  border-color: color-mix(
    in srgb,
    var(--accent) 72%,
    var(--reference-glass-highlight)
  );
  box-shadow:
    0 0 0 2px color-mix(in srgb, var(--accent) 18%, transparent),
    0 18px 52px rgba(12, 20, 22, 0.2);
  transition: none;
}

.reference-peek-mode .reference-back,
.reference-peek-mode .reference-pin,
.reference-peek-mode .reference-mini-button {
  border-color: color-mix(in srgb, var(--line) 64%, transparent);
  background: color-mix(in srgb, var(--panel) 66%, transparent);
  box-shadow: inset 0 1px 0 color-mix(
    in srgb,
    var(--reference-glass-highlight) 58%,
    transparent
  );
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
}

.reference-peek-mode .reference-back { white-space: nowrap; }
.reference-peek-mode .reference-float-caption { display: block; flex: 1 1 auto; }
.reference-peek-mode .reference-float-caption::before {
  content: "⠿";
  margin-right: 6px;
  color: var(--muted);
  font-size: 16px;
}

.reference-peek-mode.reference-minimized .reference-panel {
  height: auto !important;
  min-height: 0;
}

.reference-peek-mode.reference-minimized .reference-preview { height: auto; }
.reference-peek-mode.reference-minimized .reference-preview-toolbar { border-bottom: 0; }
.reference-peek-mode.reference-minimized .reference-preview-content { display: none; }

.reference-resize-handle { display: none; }

@media (min-width: 768px) {
  .reference-peek-mode:not(.reference-minimized) .reference-resize-handle {
    position: absolute;
    z-index: 8;
    display: block;
    touch-action: none;
    user-select: none;
    -webkit-user-select: none;
  }

  .reference-resize-n,
  .reference-resize-s {
    right: 30px;
    left: 30px;
    height: 18px;
    cursor: ns-resize;
  }

  .reference-resize-n { top: -7px; }
  .reference-resize-s { bottom: -7px; }

  .reference-resize-e,
  .reference-resize-w {
    top: 30px;
    bottom: 30px;
    width: 18px;
    cursor: ew-resize;
  }

  .reference-resize-e { right: -7px; }
  .reference-resize-w { left: -7px; }

  .reference-resize-ne,
  .reference-resize-nw,
  .reference-resize-se,
  .reference-resize-sw {
    width: 34px;
    height: 34px;
  }

  .reference-resize-ne { top: -7px; right: -7px; cursor: nesw-resize; }
  .reference-resize-nw { top: -7px; left: -7px; cursor: nwse-resize; }
  .reference-resize-se { right: -7px; bottom: -7px; cursor: nwse-resize; }
  .reference-resize-sw { bottom: -7px; left: -7px; cursor: nesw-resize; }

  .reference-resize-se::before,
  .reference-resize-se::after {
    content: "";
    position: absolute;
    right: 7px;
    bottom: 7px;
    border-right: 2px solid color-mix(in srgb, var(--accent) 76%, transparent);
    border-bottom: 2px solid color-mix(in srgb, var(--accent) 76%, transparent);
    border-radius: 0 0 3px;
    pointer-events: none;
  }

  .reference-resize-se::before { width: 14px; height: 14px; }
  .reference-resize-se::after { width: 8px; height: 8px; }
}

.back-to-top {
  position: fixed;
  right: 18px;
  bottom: 18px;
  z-index: 60;
  opacity: 0;
  pointer-events: none;
  transition: opacity 160ms ease;
}

.back-to-top.visible { opacity: 1; pointer-events: auto; }

.paired-reading-shell {
  min-height: 100vh;
  padding: 20px 22px 34px;
  background: var(--bg);
}

.paired-reader-header {
  position: sticky;
  top: 0;
  z-index: 18;
  margin-bottom: 14px;
  box-shadow: 0 8px 24px rgba(24, 35, 45, 0.08);
}

.paired-reader-actions { align-items: center; }
.paired-reader-mode { flex: 0 0 auto; }
.paired-chapter-nav { display: inline-flex; gap: 8px; }

.paired-mobile-tabs {
  display: none;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 4px;
  padding: 4px;
  border: 1px solid var(--line);
  border-radius: 7px;
  background: var(--control-bg);
}

.paired-mobile-tab {
  min-height: 38px;
  border: 0;
  border-radius: 5px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font-weight: 730;
}

.paired-mobile-tab.active {
  background: var(--panel);
  color: var(--accent);
  box-shadow: 0 1px 4px rgba(20, 35, 38, 0.1);
}

.paired-grid { gap: 16px; }
.paired-pane { border-radius: 8px; }
.paired-pane-scroll {
  height: calc(100vh - 162px);
  padding: 24px 28px 42px;
  font-size: var(--reader-font-size);
  line-height: var(--reader-line-height);
  overscroll-behavior: contain;
}

.paired-pane-scroll .meta { display: none; }
.paired-pane-scroll .page-title { font-size: 24px; }
.paired-toc-link.active { background: var(--control-bg); color: var(--accent-2); }

@media (max-width: 1439px) {
  .site-topbar { display: flex; }
  .layout,
  .layout.paired-layout { display: block; }
  .sidebar {
    position: fixed;
    top: 0;
    bottom: 0;
    left: 0;
    width: min(88vw, 326px);
    height: 100vh;
    border-right: 1px solid var(--line);
    border-bottom: 0;
    box-shadow: 18px 0 42px rgba(18, 28, 30, 0.18);
    transform: translateX(-105%);
    transition: transform 180ms ease;
  }
  body.nav-open { overflow: hidden; }
  body.nav-open .sidebar { transform: translateX(0); }
  body.nav-open .sidebar-overlay { display: block; }
  .sidebar-close { display: inline-grid; }
  .content-shell,
  .content-shell.has-page-toc {
    display: block;
    padding: 28px 34px 72px;
  }
  .toc-sidebar { display: none; }
  .inline-page-toc { display: block; }
  .paired-reading-shell { padding-top: 16px; }
  .paired-reader-header { top: var(--topbar-height); }
}

@media (max-width: 1099px) {
  .paired-reader-header {
    position: relative;
    top: auto;
    align-items: stretch;
  }
  .paired-reader-actions { width: 100%; }
  .paired-reader-actions > .mode-switch { display: none; }
  .paired-mobile-tabs { display: grid; width: 100%; }
  .paired-mobile-tabs {
    position: sticky;
    top: var(--topbar-height);
    z-index: 17;
    margin-bottom: 12px;
    background: var(--control-bg);
  }
  .paired-grid { display: block; }
  .paired-grid .paired-pane { display: none; }
  .paired-grid[data-active-pane="translation"] .paired-pane[data-paired-pane="translation"] { display: block; }
  .paired-grid[data-active-pane="note"] .paired-pane[data-paired-pane="note"] { display: grid; }
  .paired-pane-scroll {
    height: auto;
    max-height: none;
    overflow: visible;
  }
  .paired-note-stage > .paired-pane-scroll { height: auto; }
  .paired-aux-view {
    height: calc(100dvh - var(--topbar-height) - 78px);
    min-height: 440px;
  }
  .paired-aux-open,
  .paired-aux-return { min-height: 44px; }
  .paired-page.paired-aux-active { overflow: hidden; }
  .paired-page.paired-aux-active .paired-mobile-tabs {
    position: fixed;
    top: var(--topbar-height);
    right: 12px;
    left: 12px;
    z-index: 19;
    width: auto;
    margin: 0;
  }
  .paired-page.paired-aux-active [data-paired-note-panel] {
    position: fixed;
    inset: calc(var(--topbar-height) + 48px) 12px 0;
    z-index: 18;
    width: auto;
    grid-template-rows: auto minmax(0, 1fr);
    overflow: hidden;
    border: 1px solid var(--line);
    border-bottom: 0;
    border-radius: 7px 7px 0 0;
    background: var(--panel);
    box-shadow: 0 12px 30px rgba(38, 55, 62, 0.14);
  }
  .paired-page.paired-aux-active .paired-note-stage {
    min-height: 0;
    overflow: hidden;
  }
  .paired-page.paired-aux-active .paired-aux-view {
    height: 100%;
    min-height: 0;
  }
  [id^="translation-"],
  [id^="note-"] { scroll-margin-top: 118px; }
  .content mjx-container[display="true"],
  .paired-pane-scroll mjx-container[display="true"],
  .formula-container {
    overflow: visible;
    padding-left: 8px;
    padding-right: 8px;
  }
  .content mjx-container[jax="SVG"][display="true"] > svg,
  .paired-pane-scroll mjx-container[jax="SVG"][display="true"] > svg {
    max-width: 100%;
    height: auto;
  }
  .paired-toc-panel {
    position: fixed;
    top: calc(var(--topbar-height) + 12px);
    left: 16px;
    right: 16px;
    width: auto;
    max-height: calc(100vh - var(--topbar-height) - 28px);
  }
}

@media (min-width: 768px) and (max-width: 1199px) {
  .reference-panel {
    width: min(680px, calc(100% - 28px));
  }
  .reference-head {
    padding-top: max(18px, env(safe-area-inset-top));
    padding-right: max(20px, env(safe-area-inset-right));
  }
  .reference-search-row,
  .reference-filters {
    padding-right: max(20px, env(safe-area-inset-right));
  }
  .reference-browse,
  .reference-preview-content {
    padding-bottom: env(safe-area-inset-bottom);
  }
}

@media (max-width: 767px) {
  .site-topbar { padding: 8px 12px; }
  .topbar-button { min-width: 36px; min-height: 36px; padding: 4px 8px; font-size: 13px; }
  .semantic-copy-popover { min-height: 52px; }
  .semantic-copy-button { min-height: 44px; padding: 8px 11px; font-size: 14px; }
  .content-shell,
  .content-shell.has-page-toc { padding: 18px 16px 56px; }
  .content,
  .content-shell.has-page-toc .content { padding: 10px 0 58px; }
  .page-title { font-size: 26px; }
  .reader-toolbar { align-items: stretch; }
  .mode-switch { width: 100%; }
  .mode-switch a { flex: 1 1 0; justify-content: center; }
  .reader-toolbar-actions { width: 100%; }
  .reader-toolbar-actions > * { flex: 1 1 auto; }
  .page-action-button { justify-content: center; }
  .reader-popover,
  .inline-toc-panel {
    position: fixed;
    top: calc(var(--topbar-height) + 10px);
    left: 12px;
    right: 12px;
    width: auto;
    max-height: calc(100vh - var(--topbar-height) - 24px);
  }
  .chapter-pager { grid-template-columns: 1fr; }
  .chapter-pager-link.next { text-align: left; }
  .home-chapter-grid { grid-template-columns: 1fr; }
  .continue-reading { align-items: flex-start; flex-direction: column; }
  .paired-reading-shell { padding: 12px 12px 34px; }
  .paired-reader-header { padding: 12px; }
  .paired-reader-title { font-size: 18px; }
  .paired-reader-subtitle { display: none; }
  .paired-pane-head { padding: 9px 10px; }
  .paired-pane-heading { gap: 6px; }
  .paired-pane-title { max-width: 34vw; font-size: 13px; }
  .paired-aux-return { padding: 5px 8px; }
  .paired-aux-view {
    height: calc(100dvh - var(--topbar-height) - 72px);
    min-height: 360px;
  }
  .paired-pane-scroll { padding: 22px 18px 38px; }
  .content mjx-container[display="true"][style*="min-width"],
  .paired-pane-scroll mjx-container[display="true"][style*="min-width"] {
    width: calc(100% + 24px);
    margin-left: -12px;
    margin-right: -12px;
    font-size: 0.88em;
  }
  .paired-pane-scroll .page-title { font-size: 22px; }
  .paired-toc-menu { flex: 1 1 0; }
  .paired-toc-summary { width: 100%; justify-content: center; }
  .search-overlay { padding: 12px; place-items: start center; }
  .search-panel { max-height: calc(100vh - 24px); }
  .search-results { max-height: calc(100vh - 138px); }
  .reference-overlay { background: var(--panel); }
  .reference-panel {
    width: 100%;
    border-left: 0;
    box-shadow: none;
  }
  .reference-head { padding: 13px 16px 9px; }
  .reference-search-row { padding: 0 16px 10px; }
  .reference-filters { padding: 0 16px 10px; }
  .reference-preview-toolbar { padding: 10px 16px 9px; }
  .reference-preview-content { padding: 0 16px 26px; }
  .reference-preview-title { font-size: 21px; }
  .reference-overlay.reference-peek-mode { background: transparent; }
  .reference-peek-mode .reference-panel {
    top: auto !important;
    right: 0 !important;
    bottom: 0 !important;
    left: 0 !important;
    width: 100%;
    height: min(72vh, 620px);
    min-width: 0;
    min-height: 0;
    overflow: hidden;
    border: 1px solid var(--line);
    border-bottom: 0;
    border-radius: 8px 8px 0 0;
    box-shadow: 0 -16px 42px rgba(12, 20, 22, 0.22);
  }
  .reference-peek-mode .reference-preview-toolbar {
    padding: 8px 10px;
    cursor: default;
    touch-action: auto;
  }
  .reference-peek-mode .reference-float-caption { display: none; }
  .reference-peek-mode .reference-float-caption::before { content: none; }
  .learning-checklist-toolbar { gap: 10px; }
  .learning-checklist-progress { align-items: flex-start; flex-direction: column; gap: 5px; }
  .learning-checklist-progress-track { width: 100%; }
  .learning-checklist-label { padding: 10px 12px; }
  table.learning-checklist-table,
  .learning-checklist-table tbody { display: block; width: 100%; }
  .learning-checklist-table thead {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
    white-space: nowrap;
  }
  .learning-checklist-table tbody { display: grid; }
  .learning-checklist-table tbody tr {
    display: grid;
    grid-template-columns: 34px minmax(0, 1fr);
    gap: 2px 8px;
    padding: 11px 12px;
    border-bottom: 1px solid var(--line);
  }
  .learning-checklist-table tbody tr:last-child { border-bottom: 0; }
  .learning-checklist-table td {
    display: block;
    padding: 0;
    border: 0;
  }
  .learning-checklist-table td.study-check-control {
    grid-row: 1 / span 2;
    width: auto;
    padding: 1px 0 0;
    text-align: left;
  }
  .learning-checklist-table td:nth-child(2) { font-weight: 720; }
  .learning-checklist-table td:nth-child(3) { grid-column: 2; color: var(--muted); }
}

@media (prefers-reduced-transparency: reduce) {
  .semantic-copy-popover,
  .reference-peek-mode .reference-panel,
  .reference-peek-mode .reference-preview,
  .reference-peek-mode .reference-preview-toolbar,
  .reference-peek-mode .reference-back,
  .reference-peek-mode .reference-pin,
  .reference-peek-mode .reference-mini-button {
    background: var(--panel);
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

@media print {
  :root { --panel: #ffffff; --ink: #111111; --muted: #4a4a4a; --line: #cccccc; }
  body { background: #ffffff; color: #111111; }
  .site-topbar,
  .sidebar,
  .sidebar-overlay,
  .semantic-copy-popover,
  .reference-overlay,
  .paired-aux-actions,
  .paired-aux-view,
  .learning-checklist-toolbar,
  .reading-progress,
  .reader-toolbar,
  .toc-sidebar,
  .chapter-pager,
  .back-to-top,
  .paired-reader-header,
  .paired-mobile-tabs { display: none !important; }
  .layout,
  .layout.paired-layout,
  .content-shell,
  .content-shell.has-page-toc,
  .paired-grid { display: block; }
  .content-shell,
  .content-shell.has-page-toc,
  .paired-reading-shell { padding: 0; }
  .content,
  .content-shell.has-page-toc .content,
  .paired-pane-scroll { max-width: none; height: auto; overflow: visible; padding: 0; }
  .paired-pane { display: block !important; margin-bottom: 24px; border: 0; box-shadow: none; }
  .paired-pane-head { position: static; }
  .theorem-box,
  .semantic-card,
  figure,
  pre,
  table { break-inside: avoid; }
  a { color: #111111; text-decoration: none; }
}