:root {
  color-scheme: light dark;
  --bg: #f7f8fb;
  --surface: #ffffff;
  --ink: #17202a;
  --muted: #5f6978;
  --line: #dce2ea;
  --accent: #0b63ce;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #101114;
    --surface: #17191e;
    --ink: #f2f4f8;
    --muted: #a5adba;
    --line: #303641;
  }
}

* { box-sizing: border-box; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--bg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.65;
}
body > div { width: min(920px, calc(100% - 32px)); margin: 0 auto; padding: 48px 0; }
header { margin-bottom: 24px; }
h1, h2, h3 { color: var(--ink); line-height: 1.2; }
h1 { margin: 0; font-size: clamp(2rem, 5vw, 3.25rem); letter-spacing: -.04em; }
h2 { margin: 2.25rem 0 .85rem; padding-bottom: .55rem; border-bottom: 1px solid var(--line); font-size: 1.45rem; }
h3 { margin: 1.5rem 0 .75rem; font-size: 1.1rem; }
p, li { color: var(--muted); }
p { margin: 0 0 1rem; }
header p { margin-top: 10px; font-size: .95rem; }
main { padding: clamp(24px, 5vw, 44px); border: 1px solid var(--line); border-radius: 16px; background: var(--surface); box-shadow: 0 20px 60px rgb(20 36 58 / 8%); }
ul, ol { margin: 0 0 1rem; padding-left: 1.4rem; }
li + li { margin-top: .45rem; }
a { color: var(--accent); text-underline-offset: 3px; }
strong { color: var(--ink); }

@media (max-width: 560px) {
  body > div { padding: 32px 0; }
  main { padding: 22px; }
}