:root {
  --page-bg: #ffffff;
  --surface-bg: #eaf2fb;
  --surface-alt: #f7fbff;
  --surface-border: #d6e4f5;
  --text-main: #1f2d3d;
  --text-muted: #4e6279;
  --blue-strong: #0f3368;
  --blue-mid: #1c4b8f;
  --blue-soft: #78aae6;
  --grass-green: #4f8a57;
  --prey-blue: #2d5fba;
  --predator-red: #b64628;
  --predator-deep: #7d1e24;
  --trait-blue: #1c4b8f;
  --shadow-soft: 0 12px 28px rgba(15, 51, 104, 0.08);
  --mono: "IBM Plex Mono", "SFMono-Regular", "Menlo", monospace;
  --sans: "IBM Plex Sans", "Avenir Next", "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  min-height: 100%;
}

body {
  font-family: var(--sans);
  color: var(--text-main);
  background: var(--page-bg);
}

code {
  font-family: var(--mono);
  font-size: 0.92em;
}

.page-shell {
  width: min(920px, calc(100vw - 32px));
  margin: 0 auto;
  padding: 16px 0 32px;
}

.hero {
  display: block;
  margin-bottom: 16px;
}

.hero-copy {
  padding: 14px 18px 16px;
  background: var(--blue-strong);
  color: #ffffff;
  border: 1px solid var(--blue-strong);
  border-radius: 0;
  box-shadow: var(--shadow-soft);
}

.hero-copy-full {
  width: 100%;
}

.hero h1,
.card h2,
.card h3 {
  margin: 0;
  line-height: 1.08;
  font-weight: 700;
}

.hero h1 {
  font-size: clamp(2.05rem, 4.1vw, 3.2rem);
  max-width: none;
  line-height: 1.06;
}

.eyebrow,
.section-eyebrow {
  margin: 0 0 6px;
  font-family: var(--mono);
  font-size: 0.82rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.hero .eyebrow,
.hero .hero-text,
.hero #bundle-note {
  color: #ffffff;
}

.hero-inline-link,
.hero-inline-link:visited {
  color: #ffffff;
}

.hero-text {
  margin: 8px 0 0;
  font-size: 0.95rem;
  line-height: 1.35;
}

.layout {
  display: grid;
  grid-template-columns: minmax(0, 2.15fr) minmax(290px, 0.95fr);
  gap: 16px;
  align-items: start;
}

.landing-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.card {
  padding: 20px;
  background: var(--surface-alt);
  border: 1px solid var(--surface-border);
  border-radius: 0;
  box-shadow: var(--shadow-soft);
}

.viewer-card {
  grid-column: 1;
}

.sidebar-column {
  grid-column: 2;
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.chart-card {
  margin: 0;
}

.legend-card {
  margin: 0;
}

.figure-section {
  margin-top: 18px;
}

.figure-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  margin-top: 16px;
}

.figure-card {
  margin: 0;
  padding: 14px;
  background: var(--surface-bg);
  border: 1px solid var(--surface-border);
}

.figure-image {
  width: 100%;
  display: block;
  border: 1px solid var(--surface-border);
  background: #ffffff;
}

.figure-caption {
  margin: 10px 0 0;
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.4;
}

.demo-card {
  display: flex;
  flex-direction: column;
  min-height: 260px;
}

.demo-text {
  margin: 0 0 16px;
  color: var(--text-main);
  line-height: 1.5;
}

.demo-meta {
  margin: 0 0 18px;
  color: var(--text-muted);
  font-size: 0.92rem;
}

.demo-link {
  margin-top: auto;
  display: inline-flex;
  width: fit-content;
  text-decoration: none;
}

.card-header {
  display: flex;
  align-items: start;
  justify-content: space-between;
  gap: 14px;
  margin-bottom: 16px;
}

.card-header-compact {
  margin-bottom: 12px;
}

.section-eyebrow {
  color: var(--blue-strong);
}

.control-row,
.slider-row {
  display: flex;
  align-items: center;
  gap: 12px;
}

.control-row {
  flex-wrap: wrap;
  margin-bottom: 14px;
}

.slider-row {
  margin-bottom: 16px;
}

.slider-row label,
.field span,
#frame-index-label,
#step-label {
  font-family: var(--mono);
  font-size: 0.84rem;
  color: var(--text-muted);
}

.field {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-left: auto;
}

.button,
select,
input[type="range"] {
  appearance: none;
  border: 1px solid var(--surface-border);
  border-radius: 0;
  outline: 0;
  font-family: var(--mono);
}

.button {
  padding: 10px 16px;
  cursor: pointer;
  font-size: 0.88rem;
  transition: filter 120ms ease;
}

.button:hover {
  filter: brightness(0.96);
}

.button-primary {
  background: var(--blue-mid);
  color: #ffffff;
  border-color: var(--blue-mid);
}

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

select {
  padding: 10px 12px;
  background: #dfeafb;
  color: var(--text-main);
}

input[type="range"] {
  flex: 1;
  height: 6px;
  background: #dfeafb;
  border-color: transparent;
}

input[type="range"]::-webkit-slider-thumb {
  appearance: none;
  width: 16px;
  height: 16px;
  background: var(--blue-mid);
  cursor: pointer;
  border: 1px solid var(--blue-strong);
  border-radius: 0;
}

input[type="range"]::-moz-range-thumb {
  width: 16px;
  height: 16px;
  background: var(--blue-mid);
  border: 1px solid var(--blue-strong);
  cursor: pointer;
  border-radius: 0;
}

.world-canvas,
.chart-canvas {
  width: 100%;
  display: block;
  border: 1px solid var(--surface-border);
  border-radius: 0;
  background: #ffffff;
}

.world-canvas {
  aspect-ratio: 1 / 1;
}

.chart-canvas {
  min-height: 240px;
}

.chart-canvas-sidebar {
  min-height: 320px;
}

.viewer-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-top: 14px;
  color: var(--text-muted);
  font-size: 0.92rem;
}

.legend-block {
  padding: 16px;
  background: var(--surface-bg);
  border: 1px solid var(--surface-border);
  border-radius: 0;
}

.legend-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 0;
}

.legend-row + .legend-row {
  margin-top: 12px;
}

.swatch {
  width: 18px;
  height: 18px;
  border: 1px solid rgba(15, 51, 104, 0.24);
}

.swatch-prey {
  background: var(--prey-blue);
}

.swatch-grass {
  background: var(--grass-green);
}

.swatch-pred-low {
  background: var(--predator-red);
}

.swatch-pred-high {
  background: var(--predator-deep);
}

.swatch-altruist {
  background: #ab3557;
}

.swatch-selfish {
  background: #2d5fba;
}

.swatch-empty {
  background: #f4efe5;
}

.chart-subtitle {
  margin: 6px 0 0;
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.4;
}

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

@media (max-width: 1120px) {
  .landing-grid,
  .figure-grid,
  .layout {
    grid-template-columns: 1fr;
  }

  .viewer-card,
  .sidebar-column {
    grid-column: auto;
  }
}

@media (max-width: 760px) {
  .page-shell {
    width: min(100vw - 18px, 920px);
    padding-top: 12px;
  }

  .hero-copy,
  .card {
    padding: 18px;
  }

  .viewer-footer,
  .slider-row,
  .control-row {
    flex-direction: column;
    align-items: stretch;
  }

  .field {
    margin-left: 0;
    justify-content: space-between;
  }
}