:root {
  --bg: #fbfaf7;
  --surface: #ffffff;
  --text: #1d1d1f;
  --muted: #5c5c66;
  --border: #e3e1da;
  --accent: #2f5d8a;
  --accent-soft: #e7eef6;
  --warn: #9a3b1f;
  --warn-soft: #f8ebe5;
  --good: #2c6e49;
  --good-soft: #e5f1ea;
  --code-bg: #f2f0ea;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #15161a;
    --surface: #1d1f24;
    --text: #e8e7e3;
    --muted: #a3a3ad;
    --border: #2e3038;
    --accent: #8db8e3;
    --accent-soft: #1f2b38;
    --warn: #f0a080;
    --warn-soft: #3a241c;
    --good: #8fd1aa;
    --good-soft: #1c3226;
    --code-bg: #24262c;
  }
}

:root[data-theme="dark"] {
  --bg: #15161a;
  --surface: #1d1f24;
  --text: #e8e7e3;
  --muted: #a3a3ad;
  --border: #2e3038;
  --accent: #8db8e3;
  --accent-soft: #1f2b38;
  --warn: #f0a080;
  --warn-soft: #3a241c;
  --good: #8fd1aa;
  --good-soft: #1c3226;
  --code-bg: #24262c;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.65 Georgia, "Iowan Old Style", "Palatino Linotype", serif;
}

main {
  max-width: 820px;
  margin: 0 auto;
  padding: 48px 16px 96px;
}

nav.top {
  font: 14px/1.4 -apple-system, "Segoe UI", Helvetica, Arial, sans-serif;
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 40px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border);
}

nav.top a { color: var(--muted); text-decoration: none; }
nav.top a[aria-current="page"] { color: var(--text); font-weight: 600; }

h1, h2, h3, h4 {
  font-family: -apple-system, "Segoe UI", Helvetica, Arial, sans-serif;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

h1 { font-size: 2.1rem; margin: 0 0 12px; }
h2 { font-size: 1.45rem; margin: 56px 0 12px; padding-top: 8px; border-top: 1px solid var(--border); }
h3 { font-size: 1.12rem; margin: 32px 0 6px; }

.lede { color: var(--muted); font-size: 1.1rem; margin-top: 0; }

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

code {
  font: 0.88em ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  background: var(--code-bg);
  padding: 1px 5px;
  border-radius: 4px;
}

table {
  width: 100%;
  border-collapse: collapse;
  font: 15px/1.45 -apple-system, "Segoe UI", Helvetica, Arial, sans-serif;
  margin: 16px 0 24px;
}

.table-wrap { overflow-x: auto; }

th, td {
  text-align: left;
  vertical-align: top;
  padding: 8px 10px;
  border-bottom: 1px solid var(--border);
}

th { color: var(--muted); font-weight: 600; font-size: 13px; text-transform: uppercase; letter-spacing: 0.04em; }
td.num, th.num { text-align: right; font-variant-numeric: tabular-nums; }
td.sub { padding-left: 28px; }

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 18px 20px;
  margin: 18px 0;
}

.card h3 { margin-top: 0; }

.aka {
  font: 13px/1.4 -apple-system, "Segoe UI", Helvetica, Arial, sans-serif;
  color: var(--muted);
  margin: -2px 0 10px;
}

.label {
  display: inline-block;
  font: 600 12px/1 -apple-system, "Segoe UI", Helvetica, Arial, sans-serif;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 4px 7px;
  border-radius: 4px;
  margin-right: 6px;
}

.label.symptom { background: var(--warn-soft); color: var(--warn); }
.label.fix { background: var(--good-soft); color: var(--good); }
.label.source { background: var(--accent-soft); color: var(--accent); }

.callout {
  border-left: 3px solid var(--accent);
  background: var(--accent-soft);
  padding: 12px 16px;
  border-radius: 0 8px 8px 0;
  margin: 20px 0;
}

.callout.warn { border-color: var(--warn); background: var(--warn-soft); }

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 14px;
}

.grid .card { margin: 0; }
.grid .card a { font-weight: 600; text-decoration: none; }

ol.refs { font-size: 15px; color: var(--muted); }
ol.refs li { margin-bottom: 6px; }

footer { margin-top: 64px; font: 13px/1.5 -apple-system, sans-serif; color: var(--muted); }

figure.diagram {
  margin: 24px 0 28px;
}

figure.diagram .scroll { overflow-x: auto; }

figure.diagram svg {
  display: block;
  width: 100%;
  min-width: 600px;
  height: auto;
}

figure.diagram figcaption {
  font: 14px/1.5 -apple-system, "Segoe UI", Helvetica, Arial, sans-serif;
  color: var(--muted);
  margin-top: 8px;
}

.diagram text {
  font-family: -apple-system, "Segoe UI", Helvetica, Arial, sans-serif;
  font-size: 13px;
  fill: var(--text);
}

.diagram text.d-title { font-weight: 600; }
.diagram text.d-small { font-size: 12px; }
.diagram .d-muted { fill: var(--muted); font-size: 12px; }
.diagram text.d-bad-text { fill: var(--warn); font-weight: 600; }
.diagram text.d-good-text { fill: var(--good); font-weight: 600; }

.d-box { fill: var(--surface); stroke: var(--border); stroke-width: 1.5; }
.d-good { fill: var(--good-soft); stroke: var(--good); stroke-width: 1.5; }
.d-bad { fill: var(--warn-soft); stroke: var(--warn); stroke-width: 1.5; }
.d-accent { fill: var(--accent-soft); stroke: var(--accent); stroke-width: 1.5; }
.d-line { stroke: var(--muted); stroke-width: 1.5; fill: none; }
.d-line.bad { stroke: var(--warn); }
.d-line.good { stroke: var(--good); }
.d-line.accent { stroke: var(--accent); stroke-width: 2; }
.d-line.feed { stroke: var(--accent); stroke-dasharray: 4 3; }
.d-line.control { stroke: var(--muted); stroke-dasharray: 2 3; }
.d-line.trace { stroke: var(--warn); stroke-dasharray: 4 3; }
.d-ring { fill: none; stroke: var(--accent); stroke-width: 2.5; }
.d-arrowhead { fill: var(--muted); }

.crumb { font: 14px/1.4 -apple-system, "Segoe UI", Helvetica, Arial, sans-serif; color: var(--muted); margin: 0 0 8px; }
.crumb a { color: var(--muted); }

.pros-cons {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 14px;
}

.pros-cons .card { margin: 0; }
.pros-cons ul { padding-left: 20px; margin: 0; }
.pros-cons li { margin-bottom: 8px; }

footer.pager { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px; font-size: 14px; }

.diagram .pulse { transform-box: fill-box; transform-origin: center; }
.d-bar { fill: var(--accent); }
.d-token { fill: var(--accent); }
.d-commit { fill: var(--accent); }
.d-commit-bad { fill: var(--warn); }
.d-commit-fix { fill: var(--good); }
.d-commit-held { fill: var(--muted); }
.d-track { fill: var(--code-bg); stroke: var(--border); }
.d-seg { fill: var(--accent); }
.d-seg-wait { fill: var(--warn); }
.d-seg-diag { fill: var(--muted); }

.player {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-top: 12px;
  font: 14px/1.5 -apple-system, "Segoe UI", Helvetica, Arial, sans-serif;
}
.player button {
  font: inherit;
  padding: 6px 14px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
}
.player button:disabled { opacity: 0.45; cursor: default; }
.player-count { color: var(--muted); font-size: 13px; margin-left: 4px; }
.player button[data-action="expand"] { margin-left: auto; }
.player-steps {
  flex-basis: 100%;
  margin: 4px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(230px, 1fr));
  gap: 4px 8px;
  counter-reset: step;
}
.player-steps li { counter-increment: step; }
.player .player-steps button {
  width: 100%;
  height: 100%;
  padding: 6px 10px;
  text-align: left;
  font-size: 13px;
  line-height: 1.35;
  display: flex;
  gap: 8px;
  align-items: baseline;
}
.player .player-steps button::before { content: counter(step) "."; color: var(--muted); }
.player-steps .step-time { color: var(--muted); font-variant-numeric: tabular-nums; white-space: nowrap; }
.player-steps li[data-current] button { border-color: var(--accent); background: var(--accent-soft); }
.diagram .d-hours text { font-size: 11px; }
.scenario-dialog {
  width: min(1280px, 96vw);
  max-height: 96vh;
  padding: 16px 24px 24px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--bg);
  color: var(--text);
}
.scenario-dialog::backdrop { background: rgba(0, 0, 0, 0.6); }
.scenario-dialog h2 { margin: 0 0 8px; padding: 0; border: 0; font-size: 1.2rem; }
.scenario-dialog figure.diagram { margin: 0; }
.scenario-dialog figure.diagram svg { max-height: 62vh; }
.player-caption {
  flex-basis: 100%;
  margin: 4px 0 0;
  padding: 10px 14px;
  min-height: 4.5em;
  border-left: 3px solid var(--accent);
  background: var(--accent-soft);
}