:root {
  --bg: #121212;
  --surface: #1c1c1c;
  --text: #f3f3f0;
  --muted: #9c9c97;
  --border: #33332f;
  --accent: #8eb4f0;
  --accent-soft: #243044;
  --success: #75e0a7;
  --radius: 12px;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.4);
  color-scheme: dark;
}

[data-theme="light"] {
  --bg: #f6f6f4;
  --surface: #ffffff;
  --text: #1a1a1a;
  --muted: #6b6b6b;
  --border: #e3e3e0;
  --accent: #1f4b99;
  --accent-soft: #e8eef8;
  --success: #067647;
  --shadow: 0 1px 2px rgba(26, 26, 26, 0.04);
  color-scheme: light;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  min-height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: "IBM Plex Sans", "Segoe UI", system-ui, sans-serif;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 0.15em; }
a:hover { text-decoration-thickness: 2px; }

.wrap {
  width: min(1080px, calc(100% - 2rem));
  margin: 0 auto;
  padding-bottom: 4rem;
}

header.top {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
  align-items: center;
  justify-content: space-between;
  padding: 1.1rem 0 0.9rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 2rem;
}

.brand {
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
  color: inherit;
  text-decoration: none;
}
.brand strong { font-size: 1.05rem; letter-spacing: -0.02em; }
.brand span { color: var(--muted); font-size: 0.85rem; }

nav.links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem 0.9rem;
  align-items: center;
}
nav.links a {
  color: var(--text);
  text-decoration: none;
  font-size: 0.95rem;
}
nav.links a[aria-current="page"] { color: var(--accent); font-weight: 600; }

.btn {
  appearance: none;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  border-radius: 999px;
  padding: 0.35rem 0.75rem;
  font: inherit;
  cursor: pointer;
}
.btn:hover { border-color: var(--accent); }

h1 {
  font-size: clamp(1.8rem, 3vw, 2.4rem);
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin: 0 0 0.7rem;
}
h2 {
  font-size: 1.35rem;
  letter-spacing: -0.02em;
  margin: 2.2rem 0 0.6rem;
}
h3 { font-size: 1.05rem; margin: 1.4rem 0 0.4rem; }
p, li { color: var(--text); }
.lede, .muted { color: var(--muted); }
.lede { font-size: 1.15rem; max-width: 44rem; }

table.sheet {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
  margin: 0.8rem 0 1.4rem;
}
table.sheet th,
table.sheet td {
  border-bottom: 1px solid var(--border);
  padding: 0.55rem 0.45rem;
  text-align: left;
  vertical-align: top;
}
table.sheet th {
  color: var(--muted);
  font-weight: 600;
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
table.sheet td:first-child { white-space: nowrap; }
@media (max-width: 720px) {
  table.sheet td:first-child { white-space: normal; }
}

.rule {
  border-left: 3px solid var(--accent);
  padding: 0.15rem 0 0.15rem 0.9rem;
  margin: 0.7rem 0;
  max-width: 46rem;
}
.rule strong { display: inline; }

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 0.9rem;
  margin: 1.4rem 0 2rem;
}

.card {
  display: block;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.05rem 1.1rem;
  box-shadow: var(--shadow);
  color: inherit;
  text-decoration: none;
}
a.card:hover { border-color: var(--accent); }
.card h3 { margin: 0 0 0.35rem; }
.card p { margin: 0; color: var(--muted); font-size: 0.95rem; }
.kicker {
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 600;
  margin: 0 0 0.35rem;
}

.figure {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.85rem;
  margin: 0.8rem 0 1.1rem;
  overflow-x: auto;
}
.figure .mermaid { min-width: 520px; }
.caption {
  color: var(--muted);
  font-size: 0.95rem;
  max-width: 42rem;
  margin: 0 0 2rem;
}

ol.steps {
  padding-left: 1.2rem;
  max-width: 42rem;
}
ol.steps li { margin: 0.45rem 0; }
code, pre {
  font-family: "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.88em;
}
pre {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.85rem 1rem;
  overflow-x: auto;
}
.note {
  background: var(--accent-soft);
  border-radius: var(--radius);
  padding: 0.85rem 1rem;
  max-width: 42rem;
}

footer {
  margin-top: 3rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.9rem;
}

@media (max-width: 640px) {
  .figure .mermaid { min-width: 0; }
}