.theme-toggle {
  display: inline-grid;
  place-items: center;
  flex: 0 0 42px;
  width: 42px;
  height: 42px;
  padding: 0;
  border: 1px solid #d8dfe9;
  border-radius: 50%;
  background: #f1f5fa;
  color: #354b69;
  cursor: pointer;
}
.theme-toggle:hover {
  background: #e4edf8;
}
.theme-toggle svg {
  width: 20px;
  height: 20px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.7;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.home-header nav {
  align-items: center;
}
@media (max-width: 520px) {
  .top-actions .home-link {
    display: none;
  }
  .home-header nav {
    gap: 12px;
  }
  .theme-toggle {
    width: 38px;
    height: 38px;
    flex-basis: 38px;
  }
  .home-header {
    gap: 12px;
  }
  .topbar {
    padding-inline: 14px;
  }
  .top-actions {
    gap: 8px;
  }
}
@media screen {
  :root {
    color-scheme: light;
  }
  :root[data-theme='dark'] {
    color-scheme: dark;
    --ink: #edf2fa;
    --muted: #b4bfd0;
    --blue: #99c7ff;
    --bg: #1b2433;
    --line: #354157;
    --surface: #141b27;
    --raised: #202b3c;
    --soft: #1b2433;
    --text-secondary: #c1ccdc;
    --ink-2: #c9d3e2;
    --surface-2: #19212e;
    --accent-soft: #1f3350;
    --line-strong: #4a5a73;
    --note: #e7b85c;
    --note-soft: #2a2416;
  }
  [data-theme='dark'] body {
    background: #101620;
    color: var(--ink);
  }
  [data-theme='dark'] :is(h1, h2, h3, h4, legend, summary, dt) {
    color: var(--ink);
  }
  [data-theme='dark'] :is(p, li, dd, td, small) {
    color: var(--text-secondary);
  }
  [data-theme='dark'] a {
    color: var(--blue);
  }
  [data-theme='dark'] :is(strong, b) {
    color: inherit;
  }
  [data-theme='dark'] :is(.brand, .footer-brand) {
    color: var(--ink);
  }
  [data-theme='dark'] .topbar {
    background: #141b27ed;
    border-color: var(--line);
  }
  [data-theme='dark'] .sidebar {
    background: var(--surface);
    border-color: var(--line);
  }
  [data-theme='dark']
    :is(
      .toc a,
      .nav-kicker,
      .nav-bottom,
      .top-label,
      .brand small,
      .course-nav a,
      .home-header nav a,
      .home-link,
      .full-lecture
    ) {
    color: var(--muted);
  }
  [data-theme='dark'] :is(.toc a:hover, .icon-btn:hover, .quiz label:hover) {
    background: var(--raised);
  }
  [data-theme='dark'] .toc a[aria-current='location'] {
    color: #afd3ff;
    background: #253b59;
  }
  [data-theme='dark'] .course-nav a[aria-current] {
    color: #afd3ff;
  }
  [data-theme='dark'] .theme-toggle {
    background: #253247;
    border-color: #43546e;
    color: #f6d88e;
  }
  [data-theme='dark'] .theme-toggle:hover {
    background: #304360;
  }
  [data-theme='dark'] :is(.pill, .primary, .chapter-actions a:first-child) {
    color: #fff;
    background: #2164b5;
  }
  [data-theme='dark'] .primary:hover {
    background: #2d74c9;
  }
  [data-theme='dark'] :is(.secondary, .skip) {
    background: var(--raised);
    color: var(--ink);
    border-color: #56647b;
  }
  [data-theme='dark']
    :is(
      .card,
      .phase,
      .process-card,
      .term-grid article,
      .evolution-row article,
      .statement,
      .inline-note,
      .note,
      .interactive,
      .axis-list,
      .purpose-grid div,
      .goal-no,
      .footer
    ) {
    background: var(--soft);
    border-color: var(--line);
  }
  [data-theme='dark']
    :is(
      .card.blue,
      .evolution-row .current,
      .memory-strip,
      .process-ribbon,
      .ux-icon,
      .quiz-result
    ) {
    background: #1b304b;
    color: #b4d6ff;
  }
  [data-theme='dark'] .card.purple {
    background: #2a2540;
  }
  [data-theme='dark'] :is(.example, .support-box, .quiz, .table-wrap, .study-steps article) {
    border-color: var(--line);
  }
  [data-theme='dark'] .termline {
    background: #19283c;
    border-color: #719acb;
    color: var(--text-secondary);
  }
  [data-theme='dark'] .learning-figure img {
    filter: brightness(0.88);
  }
  [data-theme='dark'] .risk-matrix .grade-1 {
    background: #1d3524;
    color: #a9dfb5;
  }
  [data-theme='dark'] .risk-matrix .grade-2 {
    background: #29351b;
    color: #c8e09d;
  }
  [data-theme='dark'] .risk-matrix .grade-3 {
    background: #3a3218;
    color: #f0d27c;
  }
  [data-theme='dark'] .risk-matrix .grade-4 {
    background: #42281a;
    color: #f6b48f;
  }
  [data-theme='dark'] .risk-matrix .grade-5 {
    background: #45202a;
    color: #f7a9b8;
  }
  [data-theme='dark'] :is(.definition-box, .definition-quote, .summary-page .definition-quote) {
    background: #33212d;
    border-color: #674150;
    color: #ffb3c3;
  }
  [data-theme='dark'] :is(.red-text, .value-line b) {
    color: #ffb3c3;
  }
  [data-theme='dark'] .definition-box p {
    color: #f4d5de;
  }
  [data-theme='dark'] :is(.flag.blue, .visual-card mark) {
    color: #b6d6ff;
    background: #233957;
  }
  [data-theme='dark']
    :is(.flag.red, .chapter-actions a:nth-child(2), .visual-card:nth-child(2) mark) {
    color: #ffb9c8;
    background: #402635;
  }
  [data-theme='dark'] .flag:is(.bold, .underline, .bold-underline) {
    color: #eceef2;
    background: #2a2d33;
    box-shadow: inset 0 0 0 1px #4a4f59;
  }
  [data-theme='dark'] .flag.supplement {
    color: #d1d8e5;
    background: #2c3546;
  }
  [data-theme='dark']
    :is(
      .source,
      .section-index,
      .evidence a,
      .scope-note,
      .term-mini,
      .source-note,
      .reading-note,
      .hero-sub,
      .hero .lede,
      .chapter-hero .lede,
      .intro,
      .section .lead,
      .card p,
      .phase p,
      .support-box p,
      .term-grid p,
      .process-card > p,
      .process-card dd,
      .inline-note small,
      .purpose-grid span,
      .essential > span:last-child,
      .evolution-row p,
      .health-flow div > span:last-child,
      .loop-caption,
      .return-path,
      .process-note span,
      .memory-strip small,
      .term-grid small,
      .verification-grid span,
      .verification-notes,
      .recall-actions span,
      .glossary dd,
      .term-count,
      .art-caption,
      .chapter-meta,
      .card .mini,
      .axis-list p
    ) {
    color: var(--text-secondary);
  }
  [data-theme='dark']
    :is(
      .micro,
      .concept-map small,
      .visual-card small,
      .home-stats span,
      .chapter-card-head,
      .card-source,
      .home-footer,
      .study-path article > b
    ) {
    color: #b9c8e0;
  }
  [data-theme='dark']
    :is(
      .eyebrow,
      .step .deliverable,
      .demo-question,
      .term-abbr,
      .q-number,
      .participation b,
      .phase .question,
      .termline b,
      .inline-note > b,
      .process-card dt,
      .current .version-small,
      .process-ribbon span,
      .memory-strip b,
      .memory-strip span,
      .metaphors,
      .health-flow b,
      .recall-list .answer,
      .recall-list .answer b
    ) {
    color: #a9ceff;
  }
  [data-theme='dark']
    :is(
      .example-chip,
      .between,
      .flow-arrow,
      .value-line i,
      .process-ribbon i,
      .relation,
      .verification-grid b,
      .version-small,
      .home-stats b
    ) {
    color: #c2cfe3;
  }
  [data-theme='dark']
    :is(
      .health-flow > span,
      .esg-letter,
      .esg-triad .phase:nth-child(2) .esg-letter,
      .esg-triad .phase:nth-child(3) .esg-letter
    ) {
    color: #b3c4ff;
  }
  [data-theme='dark'] :is(.gradient-text) {
    background: linear-gradient(100deg, #91c6ff 12%, #c1b3ff 65%, #e1adff);
    background-clip: text;
    -webkit-background-clip: text;
    color: transparent;
  }
  [data-theme='dark'] :is(.segmented, .progress-track) {
    background: #303d52;
  }
  [data-theme='dark'] .segmented button {
    color: #c3cfe0;
  }
  [data-theme='dark'] .segmented button[aria-pressed='true'] {
    background: #435775;
    color: #fff;
  }
  [data-theme='dark'] :is(.flow-node, .dark-block .flow-node, .experience-path span) {
    background: #2c3b52;
    color: #eff5ff;
  }
  [data-theme='dark']
    :is(
      .flow-node small,
      .dark-block small,
      .dark-block p,
      .rux p,
      .rux .micro,
      .experience-path small
    ) {
    color: #c8d4e7;
  }
  [data-theme='dark'] :is(.dark-block, .rux) {
    background: #182336;
    border: 1px solid var(--line);
    color: var(--ink);
  }
  [data-theme='dark'] th {
    background: var(--surface-2);
    color: #e2eaf5;
  }
  [data-theme='dark'] caption {
    color: #e2eaf5;
  }
  [data-theme='dark']
    :is(td, th, .process-card dl > div, .glossary > div, .example-chip, .loop-caption) {
    border-color: var(--line);
  }
  [data-theme='dark'] .study-table tr + tr {
    border-color: #566984;
  }
  [data-theme='dark'] .study-table td:before {
    color: #afc9ed;
  }
  [data-theme='dark'] .glossary-search {
    background: var(--soft);
    border-color: #53647d;
    color: var(--ink);
  }
  [data-theme='dark'] .glossary-search::placeholder {
    color: #a6b4c8;
  }
  [data-theme='dark'] .essential {
    background: #1c2b40;
    border-color: #3a4d68;
    color: var(--ink);
  }
  [data-theme='dark'] .essential:hover {
    background: #263a56;
    border-color: #7197c8;
  }
  [data-theme='dark'] .keyword-pair span {
    background: #2b3e59;
    color: #d0e3ff;
  }
  [data-theme='dark'] .axis-line {
    background: var(--blue);
  }
  [data-theme='dark'] .axis-line:after {
    border-color: var(--blue);
  }
  [data-theme='dark']
    :is(.home-header, .home-stats, .home-section, .home-footer, .study-path article) {
    border-color: var(--line);
  }
  [data-theme='dark'] .home-visual {
    background: radial-gradient(ellipse, #2a2949, transparent 70%);
  }
  [data-theme='dark'] :is(.visual-card, .chapter-card) {
    background: #182231;
    border-color: #344359;
  }
  [data-theme='dark'] .visual-card {
    box-shadow: 0 18px 45px #0003;
  }
  [data-theme='dark']
    :is(
      .visual-card p,
      .home-hero .lede,
      .chapter-card-content > p,
      .study-path p,
      .study-steps p
    ) {
    color: var(--text-secondary);
  }
  [data-theme='dark'] .chapter-card-art {
    background: radial-gradient(ellipse, #213857, transparent 70%);
  }
  [data-theme='dark'] .chapter-card:nth-child(2) .chapter-card-art {
    background: radial-gradient(ellipse, #34294c, transparent 70%);
  }
  [data-theme='dark'] .chapter-card-art span {
    background: #23344b;
    border-color: #415d80;
    color: #bfdcff;
  }
  [data-theme='dark'] .chapter-card:nth-child(2) .chapter-card-art span {
    background: #332943;
    border-color: #5c4b79;
    color: #d9c4fb;
  }
  [data-theme='dark'] .material-list a {
    background: #223249;
    color: #b6d6ff;
  }
  [data-theme='dark'] .hero-art {
    background: var(--bg);
  }
  [data-theme='dark'] :is(.orb, .orb.ai) {
    background: linear-gradient(140deg, #2d3c53, #1c2738);
    border-color: #516784;
    box-shadow:
      0 18px 40px #0003,
      inset 0 0 0 4px #ffffff06;
  }
  [data-theme='dark'] :is(.orb svg, .orb span, .orb.ai svg, .connection::after) {
    color: #c2d5f4;
  }
  [data-theme='dark'] .chapter-tag {
    border-color: #57647b;
    color: #c3cee0;
  }
  [data-theme='dark'] :is(.goal b, .statement > b) {
    color: var(--ink);
  }
}
@media print {
  html {
    color-scheme: light;
  }
  .theme-toggle {
    display: none !important;
  }
}
/* Chapter 1 notes keep a light-theme gray text color unless the dark theme swaps it. */
[data-theme='dark'] .note {
  color: var(--muted);
}