:root {
  --ink: #153235;
  --deep: #0c2025;
  --text: #254144;
  --muted: #60777a;
  --paper: #ffffff;
  --wash: #eef8f4;
  --mist: #f8fbfa;
  --line: #cfe5df;
  --line-strong: #92c8bf;
  --teal: #00a2a6;
  --green: #6fb56a;
  --coral: #e98068;
  --gold: #e8b84f;
  --blue: #2b74b9;
  --panel: #ffffff;
  --shadow: 0 18px 46px rgba(20, 45, 50, 0.12);
  --radius: 8px;
  --max: 1180px;
  --heading: "Nunito Sans", "Avenir Next", Arial, sans-serif;
  --body: "Atkinson Hyperlegible", "Source Sans 3", Arial, sans-serif;
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  background: var(--paper);
}

body {
  margin: 0;
  color: var(--text);
  background:
    linear-gradient(180deg, rgba(0, 162, 166, 0.1), rgba(111, 181, 106, 0.03) 28rem, transparent 46rem),
    var(--paper);
  font-family: var(--body);
  font-size: 18px;
  line-height: 1.55;
  overflow-x: hidden;
}

img {
  display: block;
  max-width: 100%;
}

a { color: var(--blue); }

a:focus-visible,
button:focus-visible,
input:focus-visible,
textarea:focus-visible,
select:focus-visible {
  outline: 3px solid var(--gold);
  outline-offset: 3px;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(255, 255, 255, 0.94);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(12px);
}

.nav-shell {
  width: min(var(--max), calc(100% - 32px));
  min-height: 72px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-width: 0;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  text-decoration: none;
  font: 900 1rem var(--heading);
  letter-spacing: 0;
  min-width: 0;
}

.brand-mark {
  width: 34px;
  height: 34px;
  border-radius: 50%;
  background:
    linear-gradient(135deg, transparent 0 42%, rgba(255,255,255,0.95) 43% 56%, transparent 57%),
    conic-gradient(from 20deg, var(--teal), var(--green), var(--gold), var(--coral), var(--teal));
  box-shadow: inset 0 0 0 2px rgba(21, 50, 53, 0.14);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 4px;
}

.site-nav a {
  min-height: 42px;
  display: inline-flex;
  align-items: center;
  padding: 0 12px;
  border-radius: var(--radius);
  color: var(--muted);
  text-decoration: none;
  font: 800 0.9rem var(--heading);
}

.site-nav a:hover,
.site-nav a:focus,
.site-nav a[aria-current="page"] {
  color: var(--ink);
  background: var(--wash);
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 5px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper);
}

.nav-toggle span:not(.sr-only) {
  width: 20px;
  height: 2px;
  background: var(--ink);
}

.opening-panel {
  width: min(var(--max), calc(100% - 32px));
  min-height: min(760px, calc(100vh - 72px));
  margin: 0 auto;
  padding: 48px 0 34px;
  display: grid;
  grid-template-columns: minmax(0, 0.96fr) minmax(320px, 1.04fr);
  gap: 38px;
  align-items: center;
}

.opening-panel > *,
.opening-copy,
.opening-visual {
  min-width: 0;
}

.opening-copy h1,
.page-intro h1 {
  margin: 0;
  color: var(--ink);
  font-family: var(--heading);
  font-size: clamp(2.6rem, 5.8vw, 5.7rem);
  line-height: 0.98;
  letter-spacing: 0;
  overflow-wrap: anywhere;
}

.lede {
  max-width: 780px;
  margin: 22px 0 0;
  color: var(--muted);
  font-size: 1.18rem;
}

.opening-visual {
  margin: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--panel);
  box-shadow: var(--shadow);
}

.opening-visual img {
  width: 100%;
  aspect-ratio: 16 / 11;
  object-fit: cover;
}

.opening-visual figcaption {
  padding: 14px 16px;
  color: var(--muted);
  font: 800 0.88rem var(--heading);
}

.button-row,
.builder-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 26px;
}

.button {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0 16px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--panel);
  color: var(--ink);
  text-decoration: none;
  font: 900 0.92rem var(--heading);
  cursor: pointer;
  max-width: 100%;
  white-space: normal;
  text-align: center;
}

.button.primary {
  border-color: var(--teal);
  background: var(--teal);
  color: #042629;
}

.button.secondary { background: var(--wash); }
.button.quiet { color: var(--muted); }
.button:hover { transform: translateY(-1px); }

.page-shell,
.page-band {
  width: min(var(--max), calc(100% - 32px));
  margin: 0 auto;
}

.page-shell { padding: 54px 0; }

.page-band {
  padding: 62px 0;
  border-top: 1px solid var(--line);
}

.page-band.full {
  width: 100%;
  max-width: none;
  padding: 68px max(16px, calc((100% - var(--max)) / 2));
  background: linear-gradient(135deg, rgba(0, 162, 166, 0.11), rgba(232, 184, 79, 0.12));
}

.page-intro {
  width: min(900px, 100%);
  margin-bottom: 36px;
}

.section-head {
  max-width: 820px;
  margin-bottom: 28px;
}

.section-head h2,
.preview-head h2,
.page-intro h2 {
  margin: 0;
  color: var(--ink);
  font-family: var(--heading);
  font-size: clamp(2rem, 4vw, 3.4rem);
  line-height: 1.05;
  letter-spacing: 0;
}

.section-head p,
.page-intro p {
  margin: 14px 0 0;
  color: var(--muted);
}

.route-grid,
.metric-grid,
.reference-grid,
.builder-grid,
.boundary-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.metric-grid.four {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.route-card,
.metric-card,
.reference-card,
.builder-card,
.boundary-card,
.source-card {
  display: block;
  min-height: 100%;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  color: var(--text);
  text-decoration: none;
  box-shadow: 0 10px 22px rgba(20, 45, 50, 0.06);
}

.route-card:hover,
.reference-card:hover,
.builder-card:hover {
  transform: translateY(-2px);
  border-color: var(--line-strong);
}

.route-card span,
.metric-label,
.reference-card span,
.builder-file,
.field-flag,
.step-label {
  display: inline-block;
  color: var(--teal);
  font: 900 0.78rem var(--heading);
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

.route-card h3,
.metric-card h3,
.reference-card strong,
.builder-card h3,
.boundary-card h3,
.source-card h3 {
  display: block;
  margin: 10px 0 8px;
  color: var(--ink);
  font-family: var(--heading);
  font-size: 1.25rem;
  line-height: 1.18;
}

.route-card p,
.metric-card p,
.reference-card p,
.builder-card p,
.boundary-card p,
.source-card p {
  margin: 0;
  color: var(--muted);
}

.metric-card strong {
  display: block;
  margin: 10px 0 6px;
  color: var(--deep);
  font: 900 clamp(2rem, 4vw, 3.6rem) var(--heading);
  line-height: 1;
}

.metric-note {
  margin-top: 18px;
  color: var(--muted);
  font-size: 0.98rem;
}

.feature-split {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(320px, 1.1fr);
  gap: 32px;
  align-items: center;
}

.feature-panel {
  padding: 28px;
  border-radius: var(--radius);
  background: var(--deep);
  color: #eaf7f4;
  box-shadow: var(--shadow);
}

.feature-panel h2 {
  margin: 0;
  font-family: var(--heading);
  font-size: clamp(2rem, 4vw, 4rem);
  line-height: 1.02;
  letter-spacing: 0;
}

.feature-panel p { color: #bad6d3; }

.feature-list {
  display: grid;
  gap: 12px;
}

.feature-list div {
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.72);
}

.feature-list strong {
  display: block;
  color: var(--ink);
  font-family: var(--heading);
}

.feature-panel .feature-list div {
  border-color: rgba(255,255,255,0.16);
  background: rgba(255,255,255,0.06);
}

.feature-panel .feature-list strong {
  color: #ffffff;
}

.calc-panel {
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--mist);
}

.calc-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
}

.field {
  display: grid;
  gap: 8px;
  color: var(--ink);
  font: 900 0.9rem var(--heading);
}

.field input,
.field textarea,
.field select,
.preview-panel textarea {
  width: 100%;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: #ffffff;
  color: var(--text);
  font: 500 1rem var(--body);
}

.field input,
.field select {
  min-height: 44px;
  padding: 0 12px;
}

.field textarea,
.preview-panel textarea {
  padding: 12px;
  resize: vertical;
}

.scenario-output {
  margin-top: 20px;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 14px;
  align-items: start;
}

.scenario-output div {
  display: grid;
  align-content: start;
  gap: 10px;
  min-height: 124px;
  padding: 16px;
  border-radius: var(--radius);
  background: #ffffff;
  border: 1px solid var(--line);
}

.scenario-output div span {
  color: var(--muted);
  font: 900 0.76rem var(--heading);
  letter-spacing: 0.03em;
  line-height: 1.25;
  text-transform: uppercase;
}

.scenario-output div strong {
  display: block;
  color: var(--ink);
  font: 900 clamp(1.8rem, 2.6vw, 2.5rem) var(--heading);
  line-height: 0.98;
}

.scenario-output .metric-note {
  grid-column: 1 / -1;
  margin: 2px 0 0;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-left: 5px solid var(--teal);
  border-radius: 0 var(--radius) var(--radius) 0;
  background: #ffffff;
  color: var(--muted);
}

.scenario-output .metric-note strong {
  color: var(--ink);
  font-weight: 900;
}

.timeline {
  display: grid;
  gap: 14px;
}

.timeline article {
  display: grid;
  grid-template-columns: 72px minmax(0, 1fr);
  gap: 18px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #ffffff;
}

.timeline span {
  color: var(--coral);
  font: 900 1.1rem var(--heading);
}

.timeline h3 {
  margin: 0 0 6px;
  color: var(--ink);
  font-family: var(--heading);
}

.timeline p { margin: 0; color: var(--muted); }

.claim-boundary {
  padding: 16px 18px;
  border-left: 5px solid var(--coral);
  background: #fff5f2;
  color: var(--text);
  border-radius: 0 var(--radius) var(--radius) 0;
}

.builder-layout {
  display: grid;
  grid-template-columns: minmax(0, 0.95fr) minmax(320px, 0.85fr);
  gap: 24px;
  align-items: start;
}

.builder-form,
.preview-panel {
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #ffffff;
  box-shadow: 0 10px 24px rgba(20, 45, 50, 0.07);
}

.builder-form fieldset {
  margin: 0 0 20px;
  padding: 0;
  border: 0;
}

.builder-form legend {
  margin-bottom: 12px;
  color: var(--ink);
  font: 900 1.1rem var(--heading);
}

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

.field-wide { grid-column: 1 / -1; }

.field-hints {
  display: grid;
  gap: 4px;
  color: var(--muted);
  font: 500 0.88rem var(--body);
}

.checkbox-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
}

.checkbox-grid label {
  display: flex;
  gap: 8px;
  align-items: flex-start;
  color: var(--text);
  font: 700 0.95rem var(--body);
}

.preview-panel {
  position: sticky;
  top: 92px;
}

.preview-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 14px;
  margin-bottom: 12px;
}

.preview-head h2 {
  font-size: 1.4rem;
}

.preview-head span {
  color: var(--muted);
  font: 800 0.82rem var(--heading);
}

.preview-panel textarea {
  min-height: 620px;
  font-family: Consolas, "Liberation Mono", monospace;
  font-size: 0.88rem;
  line-height: 1.45;
}

.status-line {
  min-height: 24px;
  color: var(--muted);
  font-size: 0.95rem;
}

.builder-pager,
.site-pager {
  margin-top: 24px;
  display: flex;
  justify-content: space-between;
  gap: 14px;
}

.site-pager {
  width: min(var(--max), calc(100% - 32px));
  margin: 0 auto 54px;
  padding-top: 28px;
  border-top: 1px solid var(--line);
}

.pager-link {
  display: inline-flex;
  flex: 1;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  min-height: 44px;
  padding: 0 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--wash);
  color: var(--ink);
  text-decoration: none;
  font: 900 0.9rem var(--heading);
}

.pager-link span {
  color: var(--muted);
  font-size: 0.78rem;
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

.pager-link strong {
  color: var(--ink);
  font: 900 1rem var(--heading);
}

.pager-link.next {
  text-align: right;
}

.site-footer {
  border-top: 1px solid var(--line);
  background: var(--deep);
  color: #dff2ef;
}

.footer-inner {
  width: min(var(--max), calc(100% - 32px));
  margin: 0 auto;
  padding: 28px 0;
  display: flex;
  justify-content: space-between;
  gap: 24px;
}

.footer-inner p { margin: 0; max-width: 560px; }

.top-button {
  position: fixed;
  right: 18px;
  bottom: 18px;
  z-index: 30;
  width: 44px;
  height: 44px;
  border: 1px solid var(--line-strong);
  border-radius: 50%;
  background: var(--paper);
  color: var(--ink);
  box-shadow: var(--shadow);
  cursor: pointer;
  font: 900 1rem var(--heading);
}

@media (max-width: 1080px) {
  body { font-size: 17px; }
  .nav-toggle { display: inline-flex; }
  .site-nav {
    position: absolute;
    top: 72px;
    left: 16px;
    right: 16px;
    display: none;
    flex-direction: column;
    align-items: stretch;
    padding: 12px;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: #ffffff;
    box-shadow: var(--shadow);
  }
  .site-nav.is-open { display: flex; }
  .site-nav a { justify-content: center; }
  .opening-panel,
  .feature-split,
  .builder-layout {
    min-height: auto;
    grid-template-columns: minmax(0, 1fr);
  }
  .route-grid,
  .metric-grid,
  .metric-grid.four,
  .reference-grid,
  .builder-grid,
  .boundary-grid,
  .calc-grid,
  .scenario-output {
    grid-template-columns: 1fr 1fr;
  }
  .preview-panel { position: static; }
}

@media (max-width: 620px) {
  .nav-shell,
  .opening-panel,
  .page-shell,
  .page-band,
  .footer-inner {
    width: min(100% - 24px, var(--max));
  }
  .opening-copy h1,
  .page-intro h1 {
    font-size: clamp(2.3rem, 12vw, 3.35rem);
  }
  .button-row,
  .builder-actions {
    display: grid;
    grid-template-columns: 1fr;
    align-items: start;
    width: 100%;
  }
  .button-row .button,
  .builder-actions .button {
    width: 100%;
  }
  .route-grid,
  .metric-grid,
  .metric-grid.four,
  .reference-grid,
  .builder-grid,
  .boundary-grid,
  .calc-grid,
  .scenario-output,
  .form-grid,
  .checkbox-grid {
    grid-template-columns: 1fr;
  }
  .timeline article {
    grid-template-columns: 1fr;
  }
  .footer-inner {
    display: grid;
  }
  .builder-pager {
    display: grid;
  }
  .site-pager {
    width: min(100% - 24px, var(--max));
    display: grid;
  }
  .pager-link,
  .pager-link.next {
    text-align: left;
  }
}