:root {
  --bg-ink: #17212b;
  --bg-muted: #56616d;
  --bg-line: #d9dfe5;
  --bg-paper: #ffffff;
  --bg-ground: #f4f6f7;
  --bg-red: #ad2c24;
  --bg-red-soft: #fff1ef;
  --bg-green: #176b57;
  --bg-green-soft: #eaf7f2;
  --bg-blue: #2457a6;
  --bg-blue-soft: #edf4ff;
  --bg-gold: #8a5a00;
  --bg-gold-soft: #fff6dd;
  --bg-violet: #684294;
  --bg-violet-soft: #f5effb;
}

* {
  box-sizing: border-box;
  letter-spacing: 0;
}

.bg-body {
  margin: 0;
  color: var(--bg-ink);
  background: var(--bg-ground);
  font-family: Inter, "Noto Sans", "Segoe UI", Arial, sans-serif;
  font-size: 18px;
  line-height: 1.72;
}

.bg-body button,
.bg-body input,
.bg-body select,
.bg-body textarea {
  font: inherit;
}

.bg-page {
  width: min(1380px, calc(100% - 32px));
  margin: 0 auto;
  padding: 26px 0 70px;
}

.bg-breadcrumb,
.bg-breadcrumb a,
.bg-kicker,
.bg-edition,
.bg-method-warning,
.bg-source-links,
.bg-model-flow,
.bg-chart-note {
  display: flex;
  align-items: center;
}

.bg-breadcrumb {
  gap: 10px;
  margin: 0 0 18px;
  color: var(--bg-muted);
  font-size: 0.98rem;
}

.bg-breadcrumb a {
  gap: 7px;
  color: var(--bg-blue);
  font-weight: 760;
  text-decoration: none;
}

.bg-breadcrumb a:hover,
.bg-sources a:hover {
  text-decoration: underline;
}

.bg-breadcrumb svg,
.bg-kicker svg,
.bg-edition svg {
  width: 19px;
  height: 19px;
}

.bg-hero {
  display: grid;
  grid-template-columns: minmax(0, 1.55fr) minmax(380px, 0.75fr);
  gap: 36px;
  padding: 36px 0 40px;
  border-top: 4px solid var(--bg-red);
  border-bottom: 1px solid var(--bg-line);
}

.bg-kicker {
  gap: 8px;
  margin: 0 0 9px;
  color: var(--bg-red);
  font-size: 0.9rem;
  font-weight: 820;
  text-transform: uppercase;
}

.bg-hero h1 {
  margin: 0;
  color: #111b25;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 3.35rem;
  font-weight: 700;
  line-height: 1.06;
}

.bg-lead {
  max-width: 900px;
  margin: 18px 0 0;
  color: #34414d;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.28rem;
  line-height: 1.72;
}

.bg-edition {
  flex-wrap: wrap;
  gap: 10px 22px;
  margin: 24px 0 16px;
  color: var(--bg-muted);
  font-size: 0.96rem;
}

.bg-edition span {
  display: inline-flex;
  align-items: center;
  gap: 7px;
}

.bg-edition svg {
  color: var(--bg-green);
}

.bg-hero-metrics {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  align-self: start;
  margin: 0;
  border: 1px solid var(--bg-line);
  background: var(--bg-paper);
}

.bg-hero-metrics div {
  min-height: 100px;
  padding: 17px 18px;
  border-right: 1px solid var(--bg-line);
  border-bottom: 1px solid var(--bg-line);
}

.bg-hero-metrics div:nth-child(2n) {
  border-right: 0;
}

.bg-hero-metrics div:nth-last-child(-n + 2) {
  border-bottom: 0;
}

.bg-hero-metrics dt,
.bg-live-metrics dt,
.bg-length-metrics dt {
  color: var(--bg-muted);
  font-size: 0.9rem;
  font-weight: 740;
}

.bg-hero-metrics dd,
.bg-live-metrics dd {
  margin: 6px 0 0;
  color: var(--bg-red);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.75rem;
  font-weight: 700;
  line-height: 1.15;
}

.bg-live {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(520px, 1fr);
  gap: 34px;
  align-items: center;
  margin: 28px 0;
  padding: 26px 28px;
  border-left: 5px solid var(--bg-green);
  background: var(--bg-paper);
  box-shadow: 0 8px 26px rgba(23, 33, 43, 0.06);
}

.bg-live h2,
.bg-panel-heading h2,
.bg-reference > h2 {
  margin: 0;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 2.15rem;
  line-height: 1.2;
}

.bg-live-heading > p:not(.bg-kicker) {
  margin: 8px 0 0;
}

.bg-method-warning {
  align-items: flex-start;
  gap: 9px;
  color: #6d4a00;
  font-size: 0.94rem;
}

.bg-method-warning svg,
.bg-chart-note svg {
  flex: 0 0 auto;
  width: 19px;
  height: 19px;
  margin-top: 4px;
}

.bg-live-metrics {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0;
  background: var(--bg-line);
  border: 1px solid var(--bg-line);
}

.bg-live-metrics div {
  min-height: 92px;
  padding: 15px 17px;
  background: var(--bg-ground);
}

.bg-live-metrics dd {
  color: var(--bg-green);
  font-size: 1.5rem;
}

.bg-tabs-shell {
  position: sticky;
  z-index: 20;
  top: 0;
  margin: 0 0 26px;
  padding: 8px 0;
  background: rgba(244, 246, 247, 0.97);
  border-bottom: 1px solid var(--bg-line);
}

.bg-tabs {
  display: flex;
  gap: 6px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.bg-tabs button {
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  justify-content: center;
  gap: 7px;
  min-height: 46px;
  padding: 8px 13px;
  color: #394653;
  background: transparent;
  border: 0;
  border-bottom: 3px solid transparent;
  cursor: pointer;
  font-size: 0.93rem;
  font-weight: 760;
}

.bg-tabs button:hover {
  color: var(--bg-red);
  background: var(--bg-paper);
}

.bg-tabs button[aria-selected="true"] {
  color: var(--bg-red);
  background: var(--bg-paper);
  border-bottom-color: var(--bg-red);
}

.bg-tabs button:focus-visible,
.bg-qa-list summary:focus-visible {
  outline: 3px solid rgba(36, 87, 166, 0.28);
  outline-offset: 2px;
}

.bg-tabs svg {
  width: 18px;
  height: 18px;
}

.bg-panel[hidden] {
  display: none;
}

.bg-panel {
  min-height: 560px;
}

.bg-panel-heading {
  max-width: 1000px;
  margin-bottom: 26px;
}

.bg-panel-heading > p:not(.bg-kicker) {
  margin: 12px 0 0;
  color: var(--bg-muted);
  font-size: 1.05rem;
}

.bg-scale-diagram,
.bg-ai-flow {
  display: flex;
  align-items: stretch;
  gap: 8px;
  margin: 24px 0 30px;
  padding: 18px;
  overflow-x: auto;
  border: 1px solid var(--bg-line);
  background: var(--bg-paper);
}

.bg-scale-diagram > div {
  flex: 1 0 145px;
  min-height: 100px;
  padding: 15px;
  border-top: 4px solid var(--bg-blue);
  background: var(--bg-blue-soft);
}

.bg-scale-diagram strong,
.bg-scale-diagram span,
.bg-ai-flow strong,
.bg-ai-flow span {
  display: block;
}

.bg-scale-diagram span,
.bg-ai-flow span {
  margin-top: 5px;
  color: var(--bg-muted);
  font-size: 0.9rem;
  line-height: 1.45;
}

.bg-scale-diagram > svg,
.bg-flow-arrow {
  align-self: center;
  flex: 0 0 21px;
  color: var(--bg-red);
}

.bg-prose-stack {
  display: grid;
  gap: 22px;
}

.bg-prose {
  padding: 28px 30px;
  border-left: 4px solid var(--bg-blue);
  background: var(--bg-paper);
}

.bg-prose h3,
.bg-model-card h3,
.bg-chart-block h3,
.bg-ai-math h3,
.bg-witness h3,
.bg-insights h3 {
  margin: 0;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.55rem;
  line-height: 1.28;
}

.bg-prose p {
  margin: 13px 0 0;
}

.bg-source-links {
  flex-wrap: wrap;
  gap: 7px;
  margin-top: 16px;
}

.bg-source-links a {
  color: var(--bg-blue);
  font-size: 0.84rem;
  font-weight: 750;
  text-decoration: none;
}

.bg-function-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(360px, 0.65fr);
  gap: 22px;
}

.bg-chart-block {
  padding: 24px;
  border: 1px solid var(--bg-line);
  background: var(--bg-paper);
}

.bg-chart-block header p {
  margin: 7px 0 0;
  color: var(--bg-muted);
}

.bg-wide-block {
  margin: 22px 0;
}

.bg-bars,
.bg-source-mix {
  display: grid;
  gap: 13px;
  margin-top: 20px;
}

.bg-bar-row {
  display: grid;
  grid-template-columns: minmax(120px, 0.38fr) minmax(180px, 1fr) 72px;
  gap: 12px;
  align-items: center;
}

.bg-bar-row > span {
  font-weight: 720;
}

.bg-bar-track,
.bg-source-track {
  position: relative;
  height: 13px;
  overflow: hidden;
  background: #e8ecf0;
}

.bg-bar-track i,
.bg-source-track i {
  display: block;
  height: 100%;
  background: var(--bg-red);
  transition: width 400ms ease;
}

.bg-bar-row b {
  text-align: right;
  color: var(--bg-red);
}

.bg-length-metrics {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 20px 0 0;
  background: var(--bg-line);
  border: 1px solid var(--bg-line);
}

.bg-length-metrics div {
  min-height: 88px;
  padding: 14px;
  background: var(--bg-ground);
}

.bg-length-metrics dd {
  margin: 5px 0 0;
  color: var(--bg-blue);
  font-size: 1.45rem;
  font-weight: 800;
}

.bg-source-row {
  display: grid;
  grid-template-columns: minmax(150px, 0.3fr) minmax(200px, 1fr) 210px;
  gap: 12px;
  align-items: center;
}

.bg-source-row > strong {
  font-size: 0.96rem;
}

.bg-source-track i {
  background: var(--bg-green);
}

.bg-source-row small {
  color: var(--bg-muted);
  text-align: right;
}

.bg-ai-flow {
  gap: 6px;
}

.bg-ai-flow article {
  flex: 1 0 150px;
  min-height: 145px;
  padding: 16px;
  border-top: 4px solid var(--bg-violet);
  background: var(--bg-violet-soft);
}

.bg-ai-flow article > svg {
  width: 25px;
  height: 25px;
  margin-bottom: 12px;
  color: var(--bg-violet);
}

.bg-ai-math {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  margin: 24px 0;
}

.bg-ai-math > div {
  padding: 24px;
  border: 1px solid var(--bg-line);
  background: var(--bg-paper);
}

.bg-ai-math p {
  color: #394753;
}

.bg-ai-math code,
.bg-model-card > code {
  display: block;
  padding: 13px;
  overflow-x: auto;
  color: #17345e;
  background: var(--bg-blue-soft);
  font-family: "Noto Sans Mono", Consolas, monospace;
  font-size: 0.91rem;
  line-height: 1.55;
}

.bg-ai-boundary {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  margin-top: 24px;
  padding: 23px 25px;
  border-left: 5px solid var(--bg-gold);
  background: var(--bg-gold-soft);
}

.bg-ai-boundary > svg {
  flex: 0 0 auto;
  width: 28px;
  height: 28px;
  color: var(--bg-gold);
}

.bg-ai-boundary h3,
.bg-ai-boundary p {
  margin: 0;
}

.bg-ai-boundary p {
  margin-top: 7px;
}

.bg-model-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px;
  margin-bottom: 24px;
}

.bg-model-card {
  padding: 25px;
  border: 1px solid var(--bg-line);
  border-top: 4px solid var(--bg-green);
  background: var(--bg-paper);
}

.bg-model-card header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 12px;
}

.bg-model-card header > span {
  color: var(--bg-red);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.45rem;
  font-weight: 800;
}

.bg-model-card header em {
  color: var(--bg-green);
  font-size: 0.82rem;
  font-style: normal;
  font-weight: 760;
}

.bg-model-question {
  color: #31404c;
  font-weight: 650;
}

.bg-model-card > code {
  margin: 14px 0;
}

.bg-limit {
  color: #6b4a04;
}

.bg-model-flow {
  flex-wrap: wrap;
  gap: 7px;
  margin-top: 16px;
}

.bg-model-flow > div {
  flex: 1 1 120px;
  min-height: 68px;
  padding: 10px;
  background: var(--bg-green-soft);
}

.bg-model-flow strong,
.bg-model-flow span {
  display: block;
}

.bg-model-flow span {
  color: var(--bg-muted);
  font-size: 0.82rem;
  line-height: 1.4;
}

.bg-model-flow > svg {
  width: 17px;
  color: var(--bg-green);
}

.bg-chart-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px;
}

.bg-chart-stage {
  display: grid;
  align-items: center;
  min-height: 300px;
  margin-top: 16px;
  overflow: hidden;
  background: var(--bg-ground);
}

.bg-chart-stage > span {
  color: var(--bg-muted);
  text-align: center;
}

.bg-chart-stage svg {
  display: block;
  width: 100%;
  height: 300px;
}

.bg-chart-note {
  align-items: flex-start;
  gap: 8px;
  margin: 14px 0 0;
  color: var(--bg-muted);
  font-size: 0.9rem;
}

.bg-witness-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
}

.bg-witness {
  padding: 23px;
  border: 1px solid var(--bg-line);
  background: var(--bg-paper);
}

.bg-witness header {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  color: var(--bg-green);
  font-size: 0.86rem;
  font-weight: 760;
}

.bg-witness header code {
  color: var(--bg-muted);
}

.bg-witness blockquote {
  margin: 16px 0;
  padding-left: 17px;
  border-left: 4px solid var(--bg-red);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.16rem;
  line-height: 1.65;
}

.bg-witness dl,
.bg-witness dd {
  margin: 0;
}

.bg-witness dl {
  display: grid;
  gap: 11px;
}

.bg-witness dt {
  color: var(--bg-muted);
  font-size: 0.82rem;
  font-weight: 800;
  text-transform: uppercase;
}

.bg-witness dd {
  margin-top: 2px;
}

.bg-insights {
  display: grid;
  gap: 14px;
  margin: 24px 0 36px;
}

.bg-insights > article {
  display: grid;
  grid-template-columns: 58px minmax(0, 1fr);
  gap: 18px;
  padding: 22px;
  border-left: 4px solid var(--bg-green);
  background: var(--bg-paper);
}

.bg-insights > article > span {
  color: var(--bg-green);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.55rem;
  font-weight: 800;
}

.bg-insights p {
  margin: 9px 0 0;
}

.bg-reference {
  margin-top: 36px;
}

.bg-qa-list {
  display: grid;
  gap: 10px;
  margin-top: 18px;
}

.bg-qa-list details {
  border: 1px solid var(--bg-line);
  background: var(--bg-paper);
}

.bg-qa-list summary {
  padding: 17px 20px;
  cursor: pointer;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.15rem;
  font-weight: 700;
}

.bg-qa-list details[open] summary {
  color: var(--bg-red);
  border-bottom: 1px solid var(--bg-line);
}

.bg-qa-list details > p,
.bg-qa-list details > .bg-source-links {
  margin: 16px 20px;
}

.bg-glossary {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-top: 18px;
  background: var(--bg-line);
  border: 1px solid var(--bg-line);
}

.bg-glossary > div {
  padding: 18px;
  background: var(--bg-paper);
}

.bg-glossary dt {
  color: var(--bg-blue);
  font-weight: 800;
}

.bg-glossary dd {
  margin: 6px 0 0;
}

.bg-source-note {
  max-width: 960px;
  padding: 14px 17px;
  border-left: 4px solid var(--bg-green);
  background: var(--bg-green-soft);
}

.bg-source-verification {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  max-width: 1080px;
  padding: 14px 17px;
  color: #184f40;
  border: 1px solid #b8dbd0;
  background: var(--bg-paper);
}

.bg-source-verification svg {
  flex: 0 0 auto;
  width: 22px;
  height: 22px;
  margin-top: 3px;
  color: var(--bg-green);
}

.bg-sources {
  display: grid;
  gap: 10px;
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
}

.bg-sources li {
  display: grid;
  grid-template-columns: 58px minmax(0, 1fr);
  gap: 14px;
  padding: 16px 18px;
  background: var(--bg-paper);
  border: 1px solid var(--bg-line);
  scroll-margin-top: 80px;
}

.bg-sources li > span {
  color: var(--bg-red);
  font-weight: 800;
}

.bg-sources cite {
  font-style: normal;
  font-weight: 680;
}

.bg-sources p {
  margin: 5px 0;
  color: var(--bg-muted);
}

.bg-sources a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--bg-blue);
  font-size: 0.9rem;
  font-weight: 750;
  text-decoration: none;
}

.bg-sources svg {
  width: 16px;
  height: 16px;
}

.bg-change {
  padding: 19px;
  border-left: 4px solid var(--bg-violet);
  background: var(--bg-paper);
}

.bg-change time {
  margin-left: 10px;
  color: var(--bg-muted);
}

.bg-change p {
  margin: 8px 0 0;
}

.bg-mini-bars {
  display: grid;
  gap: 11px;
  width: 100%;
  padding: 22px;
}

.bg-mini-bars .bg-bar-row {
  grid-template-columns: minmax(115px, 0.4fr) minmax(130px, 1fr) 68px;
}

.bg-network-label {
  fill: #263746;
  font-family: Inter, "Noto Sans", sans-serif;
  font-size: 13px;
  font-weight: 700;
}

.bg-axis-label {
  fill: #5c6873;
  font-family: Inter, "Noto Sans", sans-serif;
  font-size: 12px;
}

@media (max-width: 1040px) {
  .bg-hero,
  .bg-live,
  .bg-function-layout {
    grid-template-columns: 1fr;
  }

  .bg-ai-math {
    grid-template-columns: 1fr;
  }

  .bg-model-grid,
  .bg-chart-grid,
  .bg-witness-grid {
    grid-template-columns: 1fr;
  }

  .bg-live {
    gap: 22px;
  }
}

@media (max-width: 720px) {
  .bg-body {
    font-size: 17px;
  }

  .bg-page {
    width: min(100% - 22px, 1380px);
    padding-top: 17px;
  }

  .bg-breadcrumb {
    align-items: flex-start;
    overflow-wrap: anywhere;
  }

  .bg-hero {
    gap: 24px;
    padding: 27px 0 30px;
  }

  .bg-hero h1 {
    font-size: 2.55rem;
  }

  .bg-lead {
    font-size: 1.13rem;
  }

  .bg-hero-metrics,
  .bg-live-metrics,
  .bg-length-metrics,
  .bg-glossary {
    grid-template-columns: 1fr;
  }

  .bg-hero-metrics div,
  .bg-hero-metrics div:nth-child(2n),
  .bg-hero-metrics div:nth-last-child(-n + 2) {
    min-height: 82px;
    border-right: 0;
    border-bottom: 1px solid var(--bg-line);
  }

  .bg-hero-metrics div:last-child {
    border-bottom: 0;
  }

  .bg-live {
    padding: 21px 18px;
  }

  .bg-live h2,
  .bg-panel-heading h2,
  .bg-reference > h2 {
    font-size: 1.8rem;
  }

  .bg-tabs-shell {
    margin-inline: -11px;
    padding-inline: 11px;
  }

  .bg-prose,
  .bg-model-card,
  .bg-chart-block,
  .bg-witness {
    padding: 20px 18px;
  }

  .bg-bar-row,
  .bg-source-row {
    grid-template-columns: 1fr;
    gap: 5px;
  }

  .bg-bar-row b,
  .bg-source-row small {
    text-align: left;
  }

  .bg-ai-flow,
  .bg-scale-diagram {
    padding: 13px;
  }

  .bg-insights > article,
  .bg-sources li {
    grid-template-columns: 1fr;
  }

  .bg-chart-stage,
  .bg-chart-stage svg {
    min-height: 260px;
    height: 260px;
  }
}

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