:root {
  color-scheme: light;
  --ink: #222923;
  --muted: #5f665f;
  --quiet: #858b83;
  --paper: #fffdf8;
  --surface: #ffffff;
  --wash: #f5f1e8;
  --line: #d8d1c3;
  --accent: #9d5148;
  --blue: #366b73;
  --gold: #a87532;
  --success: #54705d;
}

* {
  box-sizing: border-box;
}

html {
  scroll-padding-top: 5.5rem;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
  line-height: 1.4;
  overflow-x: hidden;
}

a {
  color: inherit;
}

em {
  font-style: italic;
}

.skip-link {
  position: absolute;
  top: -48px;
  left: 1rem;
  z-index: 20;
  padding: 0.55rem 0.75rem;
  background: var(--ink);
  color: var(--paper);
}

.skip-link:focus {
  top: 1rem;
}

.site-header,
.site-footer,
.sheet,
.page {
  width: 100%;
  max-width: 1200px;
  margin-inline: auto;
  padding-inline: 40px;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 12;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  padding-top: 1.35rem;
  padding-bottom: 1rem;
  background: var(--paper);
  border-bottom: 1px solid var(--line);
}

.brand {
  font-size: 1rem;
  font-weight: 800;
  line-height: 1;
  text-decoration: none;
}

nav {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  font-size: 0.92rem;
  font-weight: 800;
}

nav a,
.link-row a,
.site-footer a,
.resource-list a {
  color: var(--ink);
  text-decoration-color: var(--accent);
  text-decoration-thickness: 0.12em;
  text-underline-offset: 0.22em;
}

.sheet {
  padding-top: 2.5rem;
  padding-bottom: 4rem;
}

.title-block {
  padding-bottom: 2rem;
  border-bottom: 3px solid var(--line);
}

.eyebrow {
  margin: 0 0 0.65rem;
  color: var(--accent);
  font-size: 0.76rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  line-height: 1.2;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin: 0;
}

h1 {
  max-width: 100%;
  font-size: clamp(1.65rem, 3vw, 2.25rem);
  font-weight: 900;
  letter-spacing: 0;
  line-height: 1;
}

h2 {
  font-size: clamp(1.15rem, 1.8vw, 1.45rem);
  font-weight: 900;
  line-height: 1.08;
}

.subtitle {
  max-width: 760px;
  margin-top: 0.2rem;
  font-size: clamp(1.25rem, 2.5vw, 1.9rem);
  font-weight: 900;
  line-height: 1.08;
}

.authors {
  margin-top: 1rem;
  color: var(--muted);
  font-weight: 700;
}

.link-row {
  display: flex;
  gap: 1.1rem;
  flex-wrap: wrap;
  margin-top: 1.25rem;
  font-weight: 900;
}

.argument-grid,
.bottom-grid,
.one-pager {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(2rem, 7vw, 5rem);
}

.argument-grid {
  padding-top: 3rem;
}

.argument-grid article p {
  margin-top: 0.65rem;
  max-width: 38rem;
}

.model-callout {
  max-width: none;
  margin: 0;
}

.model-callout h2 {
  font-size: clamp(1.1rem, 1.7vw, 1.35rem);
  max-width: 900px;
}

.model-callout ul,
.bottom-grid ul,
.check-list {
  margin: 0.75rem 0 0;
  padding: 0;
  list-style: none;
}

.model-callout ul {
  display: flex;
  gap: 0.35rem 1.4rem;
  flex-wrap: wrap;
}

.model-callout li,
.bottom-grid li,
.check-list li {
  margin-top: 0.25rem;
}

.model-callout li {
  flex: 1 1 320px;
  margin-top: 0;
}

.model-callout li::before,
.bottom-grid li::before,
.check-list li::before {
  content: "- ";
}

.congestion-demo {
  margin: 2.35rem 0;
  padding: 1.4rem 0 1.7rem;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.demo-intro {
  width: 100%;
  max-width: 1120px;
  margin-inline: auto;
}

.demo-copy {
  max-width: 920px;
  margin-top: 1.15rem;
  border-top: 1px solid var(--line);
  padding-top: 1rem;
}

.demo-copy p:not(.eyebrow) {
  margin-top: 0.65rem;
  max-width: 48rem;
}

.demo-note {
  color: var(--muted);
  font-size: 0.88rem;
  max-width: 60rem;
}

.demo-panel {
  width: 100%;
  max-width: 1120px;
  min-width: 0;
  margin-top: 1.15rem;
  margin-inline: auto;
  border: 1px solid var(--line);
  background: var(--surface);
  padding: 1rem;
}

.demo-status {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--line);
}

.demo-status p {
  font-weight: 900;
}

.demo-status button {
  min-height: 32px;
  border: 1px solid var(--line);
  background: var(--wash);
  color: var(--ink);
  font: inherit;
  font-size: 0.82rem;
  font-weight: 900;
  cursor: pointer;
}

.demo-takeaway {
  max-width: 840px;
  margin-top: 0.75rem;
  color: var(--ink);
  font-size: clamp(0.95rem, 1.6vw, 1.05rem);
  font-weight: 900;
  line-height: 1.18;
}

.demo-measure-note {
  max-width: 760px;
  margin-top: 0.45rem;
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 800;
  line-height: 1.25;
}

.queue-animation {
  display: block;
  width: 100%;
  height: auto;
  margin-top: 0.7rem;
}

.queue-animation text {
  fill: var(--ink);
  font-family: Arial, Helvetica, sans-serif;
}

.lane-title {
  font-size: 24px;
  font-weight: 900;
}

.lane-subtitle,
.node-label {
  fill: var(--muted);
  font-size: 14px;
  font-weight: 800;
}

.flow-line,
.abandon-line,
.return-line,
.feedback-line {
  fill: none;
  stroke: var(--quiet);
  stroke-linecap: round;
  stroke-width: 2;
}

.abandon-line {
  stroke: var(--accent);
}

.return-line {
  stroke: var(--gold);
}

.feedback-line {
  stroke: var(--gold);
}

.feedback-backdrop {
  fill: var(--accent);
  opacity: 0.06;
  stroke: none;
  transition: opacity 300ms ease;
}

.demo-panel[data-stage="1"] .feedback-backdrop {
  opacity: 0.08;
}

.demo-panel[data-stage="2"] .feedback-backdrop {
  opacity: 0.1;
}

.demo-panel[data-stage="3"] .feedback-backdrop {
  opacity: 0.12;
}

.pile-dot {
  fill: var(--accent);
  opacity: 0;
  transition: opacity 400ms ease;
}

.enroll-dot {
  fill: var(--success);
  opacity: 0;
  transition: opacity 400ms ease;
}

.base-enroll {
  opacity: 1;
}

.fresh-dot {
  fill: var(--blue);
}

.moving-dot {
  opacity: 0.92;
}

.moving-fresh {
  fill: var(--blue);
}

.moving-enroll {
  fill: var(--success);
}

.moving-abandon {
  fill: var(--accent);
}

.moving-return {
  fill: var(--gold);
}

.demo-panel[data-stage="1"] .s1,
.demo-panel[data-stage="2"] .s1,
.demo-panel[data-stage="2"] .s2,
.demo-panel[data-stage="3"] .s1,
.demo-panel[data-stage="3"] .s2,
.demo-panel[data-stage="3"] .s3 {
  opacity: 1;
}

.demo-legend {
  display: flex;
  gap: 0.55rem 1rem;
  flex-wrap: wrap;
  margin-top: 0.35rem;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 800;
  line-height: 1.2;
}

.demo-legend span {
  display: inline-flex;
  align-items: center;
  gap: 0.32rem;
}

.demo-legend i {
  width: 0.62rem;
  height: 0.62rem;
  border-radius: 999px;
  flex: 0 0 auto;
}

.legend-blue {
  background: var(--blue);
}

.legend-gold {
  background: var(--gold);
}

.legend-red {
  background: var(--accent);
}

.legend-green {
  background: var(--success);
}

.demo-metrics {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 0.75rem;
  margin-top: 0.7rem;
  padding-top: 0.8rem;
  border-top: 1px solid var(--line);
}

.demo-metrics div {
  min-width: 0;
}

.demo-metrics strong {
  display: block;
  color: var(--accent);
  font-size: clamp(1.35rem, 3vw, 2rem);
  line-height: 1;
}

.demo-metrics .metric-enroll strong {
  color: var(--success);
}

.demo-metrics .metric-return strong {
  color: var(--gold);
}

.demo-metrics span {
  display: block;
  margin-top: 0.25rem;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 800;
  line-height: 1.15;
}

.load-bars {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.75rem;
  margin-top: 0.95rem;
}

.load-bars span {
  display: block;
  margin-bottom: 0.35rem;
  font-size: 0.78rem;
  font-weight: 900;
}

.load-track {
  height: 12px;
  background: var(--wash);
  border: 1px solid var(--line);
}

.load-track i {
  display: block;
  height: 100%;
  background: var(--blue);
  transition: width 300ms ease;
}

.load-bars > div:last-child .load-track i {
  background: var(--accent);
}

.evaluation-framework {
  padding: 2rem 0 2.35rem;
  border-bottom: 1px solid var(--line);
}

.evaluation-head {
  max-width: 940px;
}

.evaluation-head p:not(.eyebrow) {
  margin-top: 0.7rem;
  max-width: 760px;
}

.evaluation-layout {
  display: grid;
  grid-template-columns: minmax(240px, 0.72fr) minmax(520px, 1.28fr);
  gap: clamp(1.5rem, 4vw, 3rem);
  margin-top: 1.45rem;
}

.intervention-list {
  display: grid;
  align-content: start;
  gap: 0.55rem;
}

.intervention-card {
  width: 100%;
  border: 1px solid var(--line);
  border-left: 4px solid transparent;
  padding: 0.75rem 0.8rem;
  background: var(--surface);
  color: var(--ink);
  cursor: pointer;
  font: inherit;
  text-align: left;
}

.intervention-card:hover,
.intervention-card:focus-visible,
.intervention-card.is-active {
  border-left-color: var(--accent);
  outline: none;
}

.intervention-card span,
.intervention-card small {
  display: block;
}

.intervention-card span {
  font-size: 0.96rem;
  font-weight: 900;
  line-height: 1.1;
}

.intervention-card small {
  margin-top: 0.35rem;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 800;
  line-height: 1.18;
}

.evaluation-panel {
  min-width: 0;
  border: 1px solid var(--line);
  background: var(--surface);
  padding: 1rem;
}

.evaluation-status {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--line);
}

.evaluation-status h3 {
  margin: 0.18rem 0 0;
  font-size: clamp(1.15rem, 2vw, 1.55rem);
  font-weight: 900;
  line-height: 1.05;
}

.mini-label {
  color: var(--accent);
  font-size: 0.72rem;
  font-weight: 900;
  letter-spacing: 0.08em;
  line-height: 1.2;
  text-transform: uppercase;
}

.effect-key {
  display: flex;
  gap: 0.65rem;
  flex-wrap: wrap;
  justify-content: flex-end;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 900;
}

.effect-key span {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

.effect-key i {
  width: 0.72rem;
  height: 0.72rem;
  border-radius: 999px;
}

.effect-direct {
  background: var(--blue);
}

.effect-indirect {
  background: var(--gold);
}

.evaluation-copy {
  margin-top: 0.8rem;
  max-width: 760px;
  font-weight: 800;
  line-height: 1.24;
}

.evaluation-figure {
  display: block;
  width: 100%;
  height: auto;
  margin-top: 0.75rem;
}

.evaluation-figure text {
  fill: var(--muted);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 15px;
  font-weight: 900;
}

.eval-zone {
  opacity: 0;
  transition: opacity 220ms ease;
}

.eval-zone-direct {
  fill: var(--blue);
}

.eval-zone-indirect {
  fill: var(--gold);
}

.eval-path {
  fill: none;
  stroke: var(--quiet);
  stroke-linecap: round;
  stroke-width: 2;
}

.effect-line {
  opacity: 0;
  stroke-width: 5;
  transition: opacity 220ms ease;
}

.effect-line.effect-direct {
  background: transparent;
  stroke: var(--blue);
}

.effect-line.effect-indirect {
  background: transparent;
  stroke: var(--gold);
}

.demand-node {
  fill: var(--blue);
}

.abandon-piece {
  fill: var(--accent);
}

.return-piece {
  fill: var(--gold);
}

.enroll-piece {
  fill: var(--success);
}

.abandon-piece,
.return-piece,
.enroll-piece {
  opacity: 0;
  transition: opacity 220ms ease, transform 220ms ease;
}

.callout {
  opacity: 0;
  transition: opacity 220ms ease;
}

.direct-callout {
  fill: var(--blue) !important;
}

.indirect-callout {
  fill: var(--gold) !important;
}

.eval-zone.is-active {
  opacity: 0.09;
}

.effect-line.is-active,
.callout.is-active {
  opacity: 1;
}

.abandon-piece.is-active,
.return-piece.is-active {
  opacity: 0.42;
  transform: translateY(-2px);
}

.enroll-piece.is-active {
  opacity: 0.95;
  transform: translateY(-4px);
}

.evaluation-metrics {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.7rem;
  margin-top: 0.65rem;
  padding-top: 0.8rem;
  border-top: 1px solid var(--line);
}

.evaluation-metrics div {
  min-width: 0;
}

.evaluation-metrics strong {
  display: block;
  color: var(--blue);
  font-size: clamp(1.35rem, 3vw, 2rem);
  font-weight: 900;
  line-height: 1;
}

.evaluation-metrics span {
  display: block;
  margin-top: 0.25rem;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 800;
  line-height: 1.15;
}

.model-figure {
  margin: 1.75rem 0 3rem;
  overflow-x: auto;
}

.model-figure svg {
  display: block;
  width: 100%;
  min-width: 720px;
  height: auto;
}

.model-figure line,
.model-figure .service-flow > path {
  fill: none;
  stroke: var(--quiet);
  stroke-linecap: round;
  stroke-width: 2;
  marker-end: url("#arrow");
}

.model-figure marker path {
  fill: var(--quiet);
  stroke: none;
}

.model-figure text {
  fill: var(--muted);
  font-size: 19px;
  font-weight: 400;
}

.model-figure .label {
  font-weight: 800;
}

figcaption {
  margin-top: 0.5rem;
  color: var(--ink);
  font-size: clamp(1rem, 1.8vw, 1.25rem);
  font-weight: 900;
  text-align: center;
}

.bottom-grid {
  padding-top: 2rem;
  border-top: 1px solid var(--line);
}

.bottom-grid article {
  min-width: 0;
}

.bottom-grid h2 {
  margin-bottom: 0.7rem;
}

.bottom-grid li {
  color: var(--ink);
  line-height: 1.25;
}

.site-footer {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  padding-top: 1.2rem;
  padding-bottom: 2rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.9rem;
}

.site-footer div {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  font-weight: 800;
}

.page {
  padding-top: 2.5rem;
  padding-bottom: 4rem;
}

.page-title {
  max-width: 900px;
  padding-bottom: 2rem;
  border-bottom: 3px solid var(--ink);
}

.page-title h1 {
  max-width: 18ch;
  font-size: clamp(2.4rem, 6vw, 5.25rem);
  line-height: 0.95;
}

.page-title p:not(.eyebrow) {
  max-width: 760px;
  margin-top: 1rem;
  color: var(--muted);
  font-size: 1.1rem;
}

.button {
  display: inline-flex;
  min-height: 42px;
  align-items: center;
  justify-content: center;
  margin-top: 1.2rem;
  border: 2px solid var(--ink);
  padding: 0.55rem 0.85rem;
  background: var(--paper);
  color: var(--ink);
  font: inherit;
  font-weight: 900;
  text-decoration: none;
  cursor: pointer;
}

.button:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.one-pager {
  margin-top: 2.4rem;
  gap: 1.6rem 4rem;
}

.one-pager article {
  padding-top: 1rem;
  border-top: 1px solid var(--line);
}

.one-pager article.wide {
  grid-column: 1 / -1;
  max-width: 880px;
}

.one-pager h2 {
  font-size: 1.25rem;
}

.one-pager p {
  margin-top: 0.65rem;
  color: var(--ink);
}

.resource-list {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-top: 1rem;
  font-weight: 900;
}

@media (max-width: 760px) {
  .site-header,
  .site-footer {
    align-items: flex-start;
    flex-direction: column;
  }

  .sheet,
  .page {
    padding-top: 2rem;
  }

  .site-header,
  .site-footer,
  .sheet,
  .page {
    width: 390px;
    max-width: 100%;
    margin-left: 0;
    margin-right: auto;
    padding-left: 20px;
    padding-right: 20px;
  }

  h1 {
    max-width: 100%;
    font-size: clamp(1.55rem, 8vw, 2.15rem);
  }

  .argument-grid,
  .congestion-demo,
  .evaluation-layout,
  .bottom-grid,
  .one-pager {
    grid-template-columns: 1fr;
    gap: 1.8rem;
  }

  .demo-panel {
    padding: 0.8rem;
  }

  .demo-status {
    align-items: flex-start;
    flex-direction: column;
    gap: 0.7rem;
  }

  .queue-animation {
    min-width: 0;
  }

  .demo-metrics,
  .load-bars,
  .evaluation-metrics {
    grid-template-columns: 1fr;
  }

  .evaluation-status {
    align-items: flex-start;
    flex-direction: column;
  }

  .effect-key {
    justify-content: flex-start;
  }

  .evaluation-panel {
    padding: 0.8rem;
  }

  .evaluation-figure {
    min-width: 0;
  }

  .model-figure {
    margin-right: -20px;
    padding-right: 20px;
  }

  .model-figure svg {
    min-width: 0;
  }

  .one-pager article.wide {
    grid-column: auto;
  }
}

@media print {
  body {
    background: #ffffff;
    color: #000000;
    font-size: 10pt;
  }

  .site-header,
  .site-footer,
  .print-button {
    display: none;
  }

  .page,
  .sheet {
    width: 100%;
    padding: 0;
  }

  .page-title,
  .title-block {
    padding-bottom: 0.5rem;
    border-bottom: 2px solid #000000;
  }

  .page-title h1,
  h1 {
    font-size: 26pt;
    max-width: none;
  }

  .one-pager,
  .congestion-demo,
  .argument-grid,
  .bottom-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 0.45in;
  }

  .demo-status button,
  .queue-animation {
    display: none;
  }

  .congestion-demo {
    break-inside: avoid;
  }

  .one-pager {
    margin-top: 0.35in;
  }

  .one-pager article {
    break-inside: avoid;
    padding-top: 0.12in;
  }
}