:root {
  color-scheme: light dark;
  --brand: #00b4e7;
  --fg: #1b2733;
  --muted: #5b6b7a;
  --bg: #dafdff;
  --card: #ffffff;
  --rule: #bfe3ee;
  --link: #007394;
}

@media (prefers-color-scheme: dark) {
  :root {
    --fg: #e6edf3;
    --muted: #9bb0c0;
    --bg: #001220;
    --card: #04202f;
    --rule: #103246;
    --link: #4cc9f0;
  }
}

html {
  background: var(--bg);
}

body {
  margin: 0;
  padding: 2.5rem 1.25rem 4rem;
  background: var(--bg);
  color: var(--fg);
  font: 16px/1.65 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

/* The column is set once, on the container. Centring each child instead
   fails the moment a child sets `margin` shorthand, which resets the auto
   side margins and pins that element to the left. */
main {
  max-width: 46rem;
  margin-inline: auto;
}

h1 {
  margin: 0 0 1.5rem;
  padding-bottom: 0.75rem;
  border-bottom: 3px solid var(--brand);
  font-size: 1.9rem;
  line-height: 1.2;
}

h2 {
  margin: 2.5rem 0 0.75rem;
  font-size: 1.25rem;
}

h3 {
  margin: 1.75rem 0 0.5rem;
  font-size: 1.05rem;
  color: var(--muted);
}

/* :visited stated explicitly: a bare `a { color }` loses on specificity to
   any `a:visited` rule a browser or stylesheet may set. */
a,
a:link,
a:visited {
  color: var(--link);
}

a:hover,
a:focus {
  color: var(--brand);
}

code {
  padding: 0.1em 0.35em;
  border-radius: 4px;
  background: color-mix(in oklab, var(--brand), transparent 88%);
  font-size: 0.9em;
}

table {
  width: 100%;
  margin: 1rem 0;
  border-collapse: collapse;
  background: var(--card);
}

th,
td {
  padding: 0.55rem 0.75rem;
  border: 1px solid var(--rule);
  text-align: left;
  vertical-align: top;
}

th {
  background: color-mix(in oklab, var(--brand), transparent 85%);
}

/* Wide content scrolls inside itself rather than the page. */
table,
pre {
  display: block;
  overflow-x: auto;
}

footer {
  max-width: 46rem;
  margin: 3rem auto 0;
  padding-top: 1rem;
  border-top: 1px solid var(--rule);
  color: var(--muted);
  font-size: 0.9rem;
}