:root {
  color-scheme: light dark;
  --paper: #fbfaf7;
  --ink: #1f2328;
  --muted: #5d646d;
  --rule: #e2dfd7;
  --accent: #2a5a8c;
  --accent-ink: #ffffff;
  --accent-soft: #e8eef5;
  --code-bg: #f3f1ea;
  --serif: "Iowan Old Style", "Palatino Linotype", Charter, Georgia, "Noto Serif", serif;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Noto Sans", sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, "DejaVu Sans Mono", monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #14171c;
    --ink: #e4e4e0;
    --muted: #9aa1aa;
    --rule: #2c3138;
    --accent: #8ab4e0;
    --accent-ink: #10141a;
    --accent-soft: #1f2a37;
    --code-bg: #1c2027;
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 1.5rem; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 1.125rem/1.7 var(--serif);
  -webkit-text-size-adjust: 100%;
}

a { color: var(--accent); text-underline-offset: 0.15em; }

/* Layout: the text column is centred, the sidebar sits in the left margin. */
main {
  max-width: 44rem;
  margin: 0 auto;
  padding: 3.5rem 1.25rem 4rem;
}

.sidebar {
  display: none;
  position: fixed;
  inset: 0 auto 0 0;
  width: 18rem;
  padding: 2rem 1.25rem;
  overflow-y: auto;
  border-right: 1px solid var(--rule);
  font: 0.875rem/1.4 var(--sans);
}

.sidebar-title {
  display: block;
  margin-bottom: 1rem;
  color: var(--ink);
  font-weight: 650;
  text-decoration: none;
}

.sidebar ol,
.mobile-toc ol { margin: 0; padding: 0; list-style: none; }

.sidebar nav a {
  display: block;
  padding: 0.4rem 0.6rem;
  border-radius: 0.3rem;
  color: var(--muted);
  text-decoration: none;
}

.sidebar nav a:hover { color: var(--ink); }

.sidebar nav a[aria-current] {
  background: var(--accent-soft);
  color: var(--ink);
}

.sidebar .download { margin-top: 1.25rem; }
.sidebar .download-info { margin: 0.4rem 0 0; }

@media (min-width: 72rem) {
  .sidebar { display: block; }
  main { margin-left: max(18rem, calc((100vw - 44rem) / 2)); }
  .mobile-toc { display: none; }
  .hero .download, .hero .download-info { display: none; }
}

/* Title block */
.hero {
  margin-bottom: 2.5rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--rule);
}

.hero h1 {
  margin: 0;
  font: 700 clamp(2.1rem, 6vw, 3rem)/1.12 var(--sans);
  letter-spacing: -0.02em;
  text-wrap: balance;
}

.tagline { margin: 1rem 0 0; color: var(--muted); font-size: 1.25rem; font-style: italic; }
.byline { margin: 0.75rem 0 1.5rem; color: var(--muted); font: 0.875rem var(--sans); }

.download {
  display: inline-block;
  padding: 0.55rem 1rem;
  border-radius: 0.35rem;
  background: var(--accent);
  color: var(--accent-ink);
  font: 600 0.9rem/1.2 var(--sans);
  text-decoration: none;
}

.download:hover { opacity: 0.88; }

.download-info {
  margin-left: 0.6rem;
  color: var(--muted);
  font: 0.8rem var(--sans);
}

.sidebar .download-info { display: block; margin-left: 0; }

.mobile-toc {
  margin-bottom: 2.5rem;
  padding: 0.75rem 1rem;
  border: 1px solid var(--rule);
  border-radius: 0.35rem;
  font: 0.95rem/1.4 var(--sans);
}

.mobile-toc summary { font-weight: 600; cursor: pointer; }
.mobile-toc li { margin-top: 0.6rem; }
.mobile-toc a { text-decoration: none; }

/* Article */
article h2 {
  margin: 3.5rem 0 1rem;
  font: 700 1.6rem/1.25 var(--sans);
  letter-spacing: -0.01em;
  text-wrap: balance;
}

article h3 {
  margin: 2.25rem 0 0.75rem;
  font: 650 1.2rem/1.3 var(--sans);
}

article p, article ul, article ol { margin: 0 0 1.1rem; }
article li { margin-bottom: 0.4rem; }
article ul, article ol { padding-left: 1.5rem; }

.headerlink {
  margin-left: 0.4rem;
  color: var(--muted);
  font-weight: 400;
  text-decoration: none;
  opacity: 0;
}

h2:hover .headerlink, h3:hover .headerlink, .headerlink:focus { opacity: 1; }

code {
  padding: 0.1em 0.3em;
  border-radius: 0.2em;
  background: var(--code-bg);
  font: 0.84em var(--mono);
  overflow-wrap: break-word;
}

.highlight {
  margin: 0 0 1.4rem;
  border-radius: 0.4rem;
  background: var(--code-bg);
  overflow-x: auto;
}

.highlight pre {
  margin: 0;
  padding: 1rem 1.1rem;
  font: 0.84rem/1.55 var(--mono);
}

.highlight code { padding: 0; background: none; font: inherit; }

.table-wrap {
  margin: 0 0 1.5rem;
  overflow-x: auto;
}

table {
  width: 100%;
  border-collapse: collapse;
  font: 0.875rem/1.45 var(--sans);
}

th, td {
  padding: 0.55rem 0.7rem;
  border-bottom: 1px solid var(--rule);
  text-align: left;
  vertical-align: top;
}

th { border-bottom: 2px solid var(--muted); font-weight: 650; }

td code, th code { font-size: 0.9em; }

/* Wide tables keep readable columns and scroll inside their own box. */
.table-wrap table { min-width: 30rem; }
.table-wrap table:has(th:nth-child(5)) { min-width: 48rem; }

footer {
  margin-top: 3.5rem;
  padding-top: 2rem;
  border-top: 1px solid var(--rule);
}

@media print {
  .sidebar, .mobile-toc, .download, .download-info, .headerlink { display: none; }
  main { margin: 0; max-width: none; padding: 0; }
}