:root {
  --text: #171717;
  --secondary: #5f6368;
  --background: #f4f5f6;
  --surface: #ffffff;
  --surface-subtle: #f8f9fa;
  --border: #d5d8dc;
  --border-strong: #aeb4bb;
  --accent: #1d4f91;
  --positive: #216e39;
  --positive-bg: #edf7ef;
  --warning: #9a4d00;
  --warning-bg: #fff4e8;
  --danger: #a12424;
}

* { box-sizing: border-box; }
html { background: var(--background); }

body {
  margin: 0;
  color: var(--text);
  background: var(--background);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans SC", Arial, sans-serif;
  font-size: 14px;
  line-height: 1.5;
}

main {
  width: min(1440px, calc(100% - 48px));
  margin: 0 auto;
  padding: 32px 0 48px;
}

.site-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 32px;
  border-bottom: 1px solid var(--border);
}

.site-nav > div { display: flex; }
.site-nav a { color: var(--secondary); text-decoration: none; }
.site-nav .brand { padding: 12px 0; color: var(--text); font-weight: 700; letter-spacing: .01em; }
.site-nav > div a { margin-bottom: -1px; padding: 12px 14px; border-bottom: 2px solid transparent; }
.site-nav > div a:hover { color: var(--text); }
.site-nav > div a.active { border-bottom-color: var(--accent); color: var(--text); font-weight: 650; }

.page-header {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 32px;
  margin-bottom: 24px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--border-strong);
}

.product-name,
.step {
  color: var(--secondary);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1 {
  margin: 6px 0 4px;
  font-size: 28px;
  line-height: 1.25;
  font-weight: 650;
  letter-spacing: -0.02em;
}

.page-header p {
  margin: 0;
  color: var(--secondary);
  font-size: 14px;
}

.model-definition {
  display: grid;
  grid-template-columns: auto auto;
  gap: 0;
  margin: 0;
  border: 1px solid var(--border);
  background: var(--surface);
}

.model-definition > div {
  min-width: 240px;
  padding: 10px 14px;
}

.model-definition > div + div { border-left: 1px solid var(--border); }
.model-definition dt { color: var(--secondary); font-size: 11px; font-weight: 700; text-transform: uppercase; }
.model-definition dd { margin: 3px 0 0; font: 13px/1.4 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; }

.workspace,
.results {
  display: grid;
  grid-template-columns: minmax(0, 1.45fr) minmax(340px, .75fr);
  gap: 16px;
}

.results {
  grid-template-columns: 1fr 1fr;
  margin-top: 16px;
}

.panel,
.result-card {
  min-width: 0;
  border: 1px solid var(--border);
  border-radius: 3px;
  background: var(--surface);
}

.panel { padding: 18px; }
.result-card { min-height: 280px; padding: 18px; }

.panel-head,
.result-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border);
}

h2 {
  margin: 3px 0 0;
  font-size: 17px;
  font-weight: 650;
  letter-spacing: -0.01em;
}

.hint {
  margin: 12px 0;
  color: var(--secondary);
  line-height: 1.55;
}

code {
  padding: 1px 4px;
  border: 1px solid #e1e3e6;
  background: #f3f4f5;
  color: #333;
  font-size: 12px;
}

textarea {
  display: block;
  width: 100%;
  min-height: 390px;
  resize: vertical;
  border: 1px solid var(--border-strong);
  border-radius: 2px;
  background: #fff;
  color: var(--text);
  padding: 13px;
  font: 14px/1.65 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  outline: none;
}

textarea:focus,
select:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px var(--accent);
}

.turn-control {
  display: grid;
  grid-template-columns: auto 100px 1fr;
  align-items: center;
  gap: 10px;
  margin-top: 12px;
  color: var(--secondary);
}

select {
  width: 100%;
  border: 1px solid var(--border-strong);
  border-radius: 2px;
  background: white;
  padding: 7px 9px;
  color: var(--text);
  font-size: 14px;
}

#visibility {
  justify-self: end;
  font: 12px/1.4 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

button {
  border: 1px solid #143d72;
  border-radius: 2px;
  background: var(--accent);
  color: white;
  padding: 8px 12px;
  font: inherit;
  font-weight: 600;
  cursor: pointer;
}

button:hover { background: #163f75; }
button:disabled { cursor: progress; opacity: .55; }

button.secondary {
  border-color: var(--border-strong);
  background: var(--surface);
  color: var(--text);
}

button.secondary:hover { background: var(--surface-subtle); }

.action-card {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  gap: 16px;
  padding: 16px 0;
  border-bottom: 1px solid var(--border);
}

.action-card strong { font-size: 14px; font-weight: 650; }
.action-card p { margin: 4px 0 0; color: var(--secondary); font-size: 13px; line-height: 1.5; }

#status {
  margin-top: 16px;
  padding: 10px 12px;
  border-left: 3px solid var(--border-strong);
  background: var(--surface-subtle);
  color: var(--secondary);
  font-size: 13px;
}

.badge {
  border: 1px solid var(--border);
  border-radius: 2px;
  padding: 4px 7px;
  background: var(--surface-subtle);
  color: var(--secondary);
  font-size: 10px;
  font-weight: 750;
  letter-spacing: .05em;
}

.badge.offer { border-color: #75aa82; background: var(--positive-bg); color: var(--positive); }
.badge.wait { border-color: #d6a46e; background: var(--warning-bg); color: var(--warning); }
.empty { margin-top: 20px; color: var(--secondary); }

.episode,
.decision-block {
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
}

.episode:first-child,
.decision-block:first-child { border-top: 0; }
.episode h3,
.decision-block h3 { margin: 0 0 8px; font-size: 15px; font-weight: 650; }
.decision-block p { margin: 12px 0; }

.meta {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 8px 0 10px;
}

.meta span,
.factor {
  border: 1px solid var(--border);
  border-radius: 2px;
  background: var(--surface-subtle);
  padding: 3px 6px;
  color: #444;
  font: 11px/1.4 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

.factor.pass { border-color: #9ac4a3; background: var(--positive-bg); color: var(--positive); }
.factor.fail { border-color: #dfadad; background: #fff0f0; color: var(--danger); }
.detail { color: var(--secondary); font-size: 13px; line-height: 1.65; }

pre {
  overflow: auto;
  border: 1px solid var(--border);
  border-radius: 2px;
  background: var(--surface-subtle);
  padding: 12px;
  font-size: 12px;
  line-height: 1.55;
}

/* Research reading view */
.research-header {
  max-width: 920px;
  margin-bottom: 28px;
}

.research-header h1 { margin-top: 8px; font-size: 30px; }
.research-header p { max-width: 820px; margin: 8px 0 0; color: var(--secondary); font-size: 15px; line-height: 1.7; }

.research-map {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: stretch;
  margin-bottom: 36px;
  border: 1px solid var(--border-strong);
  background: var(--surface);
}

.research-map-item { display: block; padding: 20px; color: var(--text); text-decoration: none; }
.research-map-item:hover { background: var(--surface-subtle); }
.research-map-item strong { display: block; margin: 6px 0 4px; font-size: 18px; }
.research-map-item p { margin: 0; color: var(--secondary); }
.map-index { color: var(--accent); font-size: 11px; font-weight: 750; letter-spacing: .07em; }
.map-relation { display: grid; place-items: center; padding: 0 18px; border-right: 1px solid var(--border); border-left: 1px solid var(--border); color: var(--secondary); font: 11px/1.3 ui-monospace, monospace; }

.research-track { margin-top: 36px; scroll-margin-top: 20px; }

.track-header {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(300px, 520px);
  align-items: end;
  gap: 28px;
  margin-bottom: 16px;
  padding: 18px 0;
  border-top: 2px solid var(--text);
  border-bottom: 1px solid var(--border-strong);
}

.track-number { color: var(--accent); font-size: 11px; font-weight: 750; letter-spacing: .07em; text-transform: uppercase; }
.track-header h2, .baseline-section h2 { margin-top: 5px; font-size: 22px; }
.track-question { margin: 0; color: var(--secondary); font: 13px/1.55 ui-monospace, SFMono-Regular, Menlo, monospace; }

.research-grid { display: grid; gap: 16px; margin-bottom: 16px; }
.research-grid.two-columns { grid-template-columns: 1fr 1fr; }

.research-section {
  border: 1px solid var(--border);
  background: var(--surface);
  padding: 20px;
}

.research-section.full-width { margin-bottom: 16px; }
.research-section h3 { margin: 0 0 14px; font-size: 16px; font-weight: 700; }
.research-section h4 { margin: 0 0 5px; font-size: 14px; }
.research-section > p { color: #35383b; line-height: 1.7; }
.research-section blockquote { margin: 0 0 16px; padding: 14px 16px; border-left: 3px solid var(--accent); background: var(--surface-subtle); font-size: 17px; font-weight: 600; }

.criteria-list { margin: 0; padding: 0; list-style: none; counter-reset: criteria; }
.criteria-list li { display: grid; grid-template-columns: 160px 1fr; gap: 12px; padding: 8px 0; border-top: 1px solid #e6e8ea; }
.criteria-list li:first-child { border-top: 0; }
.criteria-list strong { font: 12px/1.5 ui-monospace, monospace; }
.criteria-list span { color: var(--secondary); }

.comparison-table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 13px; }
th, td { padding: 10px 12px; border: 1px solid var(--border); text-align: left; vertical-align: top; }
th { background: var(--surface-subtle); color: #36393c; font-weight: 700; }
td:first-child { width: 170px; font-weight: 650; }

.reference-list, .plain-list { margin: 0; padding: 0; list-style: none; }
.reference-list li { padding: 10px 0; border-top: 1px solid #e6e8ea; }
.reference-list li:first-child { padding-top: 0; border-top: 0; }
.reference-list a { display: block; color: var(--accent); font-weight: 650; text-decoration: none; }
.reference-list a:hover { text-decoration: underline; }
.reference-list span { display: block; margin-top: 3px; color: var(--secondary); line-height: 1.55; }
.reference-list.numbered { counter-reset: reference; }
.reference-list.numbered li { position: relative; padding-left: 32px; counter-increment: reference; }
.reference-list.numbered li::before { position: absolute; left: 0; content: counter(reference, decimal-leading-zero); color: var(--secondary); font: 11px/1.6 ui-monospace, monospace; }

.finding-box, .warning-box { margin-top: 16px; padding: 12px 14px; border-left: 3px solid var(--accent); background: #f1f5fa; }
.warning-box { border-left-color: var(--warning); background: var(--warning-bg); }
.finding-box p, .warning-box p { margin: 4px 0 0; color: #444; line-height: 1.6; }

.equation-comparison { display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; gap: 20px; }
.equation-comparison > div:not(.equation-divider) { padding: 16px; border: 1px solid var(--border); background: var(--surface-subtle); }
.equation-comparison span { display: block; margin-bottom: 8px; color: var(--secondary); font-size: 12px; font-weight: 700; }
.equation-comparison code { display: block; padding: 8px; font-size: 14px; }
.equation-comparison p { margin: 10px 0 0; color: var(--secondary); font-size: 13px; }
.equation-divider { color: var(--danger); font-size: 22px; font-weight: 700; }

.label-definition { padding: 12px 0; border-top: 1px solid var(--border); }
.label-definition:first-of-type { padding-top: 0; border-top: 0; }
.label-definition p { margin: 0; color: var(--secondary); line-height: 1.6; }

.pipeline { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0; margin: 0; padding: 0; list-style: none; }
.pipeline li { display: grid; grid-template-columns: 34px 1fr; gap: 10px; padding: 4px 18px; border-left: 1px solid var(--border); }
.pipeline li:first-child { padding-left: 0; border-left: 0; }
.pipeline-index { display: grid; place-items: center; width: 28px; height: 28px; border: 1px solid var(--border-strong); font: 700 12px/1 ui-monospace, monospace; }
.pipeline p { margin: 5px 0 0; color: var(--secondary); font-size: 13px; line-height: 1.6; }

.loss-block { margin: 0 0 14px; border-left: 3px solid var(--accent); font-size: 14px; }
.plain-list li { padding: 7px 0; border-top: 1px solid #e6e8ea; color: var(--secondary); }
.plain-list li:first-child { border-top: 0; }

.use-table { display: grid; grid-template-columns: 1fr 1fr; border: 1px solid var(--border); }
.use-table > div { padding: 14px; }
.use-table > div + div { border-left: 1px solid var(--border); }
.use-table .allowed { background: var(--positive-bg); }
.use-table .disallowed { background: #fff2f2; }
.use-table ul { margin: 8px 0 0; padding-left: 18px; }
.use-table li { margin: 5px 0; }

.check-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 8px 24px; }
.check-grid span { padding: 7px 0; border-bottom: 1px solid #e6e8ea; color: #3d4144; font: 12px/1.5 ui-monospace, monospace; }

.baseline-section { margin-top: 36px; padding: 22px; border: 1px solid var(--border-strong); background: #eef0f2; }
.baseline-section > div:first-child { max-width: 840px; }
.baseline-section p { color: var(--secondary); line-height: 1.65; }
.metric-grid { display: grid; grid-template-columns: repeat(6, 1fr); margin: 20px 0 0; border: 1px solid var(--border-strong); background: var(--surface); }
.metric-grid div { padding: 12px; border-left: 1px solid var(--border); }
.metric-grid div:first-child { border-left: 0; }
.metric-grid dt { color: var(--secondary); font-size: 11px; }
.metric-grid dd { margin: 4px 0 0; font: 650 20px/1.2 ui-monospace, monospace; }
.baseline-conclusion { margin-bottom: 0; font-weight: 600; }

@media (max-width: 960px) {
  main { width: min(100% - 24px, 760px); padding-top: 20px; }
  .page-header { align-items: stretch; flex-direction: column; }
  .model-definition { grid-template-columns: 1fr; }
  .model-definition > div { min-width: 0; }
  .model-definition > div + div { border-top: 1px solid var(--border); border-left: 0; }
  .workspace, .results { grid-template-columns: 1fr; }
  textarea, input, select, button { font-size: 16px; }
  .turn-control { grid-template-columns: auto 110px; }
  #visibility { grid-column: 1 / -1; justify-self: start; }
  .research-map { grid-template-columns: 1fr; }
  .map-relation { justify-content: start; border: 0; border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); padding: 10px 20px; }
  .track-header { grid-template-columns: 1fr; }
  .research-grid.two-columns { grid-template-columns: 1fr; }
  .pipeline { grid-template-columns: 1fr; }
  .pipeline li { padding: 14px 0; border-top: 1px solid var(--border); border-left: 0; }
  .pipeline li:first-child { border-top: 0; }
  .metric-grid { grid-template-columns: repeat(3, 1fr); }
  .metric-grid div:nth-child(4) { border-left: 0; }
  .metric-grid div:nth-child(n+4) { border-top: 1px solid var(--border); }
}

@media (max-width: 560px) {
  main { width: calc(100% - 16px); }
  .panel, .result-card { padding: 14px; }
  .action-card { grid-template-columns: 1fr; }
  .action-card button { width: 100%; }
  .site-nav { align-items: flex-start; flex-direction: column; gap: 0; }
  .site-nav > div { width: 100%; }
  .site-nav > div a { flex: 1; text-align: center; }
  .equation-comparison { grid-template-columns: 1fr; }
  .equation-divider { text-align: center; }
  .criteria-list li { grid-template-columns: 1fr; gap: 2px; }
  .use-table { grid-template-columns: 1fr; }
  .use-table > div + div { border-top: 1px solid var(--border); border-left: 0; }
  .check-grid { grid-template-columns: 1fr; }
  .metric-grid { grid-template-columns: repeat(2, 1fr); }
  .metric-grid div:nth-child(odd) { border-left: 0; }
  .metric-grid div:nth-child(n+3) { border-top: 1px solid var(--border); }
}