:root {
  --bg: #fbfaf7;
  --text: #1f2430;
  --muted: #6b7280;
  --accent: #b3531a;
  --link: #1a6fb3;
  --card: #ffffff;
  --border: #e3e0d8;
  --code-bg: #f1efe9;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: Georgia, "Iowan Old Style", "Times New Roman", serif;
  font-size: 18px;
  line-height: 1.65;
}

header.masthead {
  padding: 72px 20px 40px;
  text-align: center;
  border-bottom: 1px solid var(--border);
  background: linear-gradient(180deg, #f3f1ea, var(--bg));
}

header.masthead h1 {
  font-size: 2.6rem;
  margin: 0 auto 14px;
  max-width: 820px;
  line-height: 1.2;
  font-weight: 600;
}

header.masthead .subtitle {
  color: var(--muted);
  max-width: 640px;
  margin: 0 auto;
  font-size: 1.1rem;
  font-style: italic;
}

header.masthead .byline {
  margin-top: 22px;
  font-size: 0.85rem;
  color: var(--muted);
  font-family: "Helvetica Neue", Arial, sans-serif;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 20px;
}

section.prose {
  max-width: 700px;
  margin: 0 auto;
}

h2 {
  font-size: 1.7rem;
  margin: 2.2em 0 0.6em;
  font-weight: 600;
}

h3 {
  font-size: 1.15rem;
  margin: 1.8em 0 0.5em;
  font-weight: 600;
}

p { margin: 0.9em 0; }

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

code, pre {
  font-family: "SF Mono", ui-monospace, Menlo, Consolas, monospace;
  font-size: 0.82em;
  background: var(--code-bg);
  border-radius: 4px;
}

code { padding: 0.1em 0.35em; }

pre {
  padding: 14px 16px;
  overflow-x: auto;
  line-height: 1.5;
}

.note {
  font-size: 0.9rem;
  color: var(--muted);
  border-left: 3px solid var(--border);
  padding-left: 14px;
  margin: 1.2em 0;
}

/* ----- demo cards ----- */

.demo {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  box-shadow: 0 2px 14px rgba(40, 36, 24, 0.06);
  padding: 22px;
  margin: 34px auto;
  font-family: "Helvetica Neue", Arial, sans-serif;
  font-size: 14px;
}

.demo .demo-title {
  font-weight: 600;
  font-size: 1.0rem;
  margin-bottom: 4px;
}

.demo .demo-hint {
  color: var(--muted);
  margin-bottom: 14px;
  font-size: 0.85rem;
}

.demo-flex {
  display: flex;
  flex-wrap: wrap;
  gap: 22px;
  align-items: flex-start;
  justify-content: center;
}

.demo-main { flex: 0 0 auto; }

.demo-side { flex: 0 1 360px; min-width: 260px; }

canvas.game-canvas {
  border-radius: 6px;
  display: block;
  cursor: crosshair;
  touch-action: none;
  max-width: 100%;
}

canvas.readout-canvas {
  border-radius: 4px;
  display: block;
  margin-top: 8px;
  max-width: 100%;
}

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  margin-top: 12px;
}

.controls button, .controls label.radio {
  font: inherit;
  font-size: 13px;
  padding: 5px 12px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: #faf8f3;
  cursor: pointer;
}

.controls button:hover { background: #f0ece1; }

.controls .slider-group {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: var(--muted);
}

.scoreline {
  margin-top: 10px;
  font-size: 13px;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}

.mosaic {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 6px;
}

.mosaic-tile { text-align: center; }

.mosaic-tile canvas {
  width: 100%;
  border-radius: 3px;
  display: block;
  image-rendering: pixelated;
}

.mosaic-tile span {
  font-size: 10px;
  color: var(--muted);
}

.side-label {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
  margin-bottom: 8px;
}

/* ----- figures ----- */

.figrow {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  justify-content: center;
  margin: 26px 0;
}

.fig {
  flex: 1 1 380px;
  max-width: 520px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 14px;
}

.fig svg.chart { width: 100%; height: auto; display: block; }

.fig .caption, .demo .caption {
  font-size: 0.84rem;
  color: var(--muted);
  font-family: Georgia, serif;
  margin-top: 8px;
  line-height: 1.5;
}

svg.chart .gridline { stroke: #eceae3; stroke-width: 1; }
svg.chart .axis { stroke: #9a958a; stroke-width: 1; }
svg.chart .ticklabel { font: 11px "Helvetica Neue", Arial, sans-serif; fill: #6b7280; }
svg.chart .axislabel { font: 12px "Helvetica Neue", Arial, sans-serif; fill: #374151; }
svg.chart .charttitle { font: 600 13px "Helvetica Neue", Arial, sans-serif; fill: #1f2430; }
svg.chart .legendlabel { font: 11.5px "Helvetica Neue", Arial, sans-serif; fill: #374151; }

/* architecture diagram */
.arch-fig {
  max-width: 760px;
  margin: 26px auto;
}
.arch-fig svg { width: 100%; height: auto; }

footer {
  margin-top: 70px;
  padding: 30px 20px 60px;
  border-top: 1px solid var(--border);
  text-align: center;
  color: var(--muted);
  font-size: 0.85rem;
}

@media (max-width: 720px) {
  header.masthead h1 { font-size: 1.9rem; }
  .demo { padding: 14px; }
}