:root {
  --bg: #ffffff; --fg: #1f1f24; --muted: #5d5d6b; --line: #e5e5ec; --accent: #3446ff; --soft: #f5f6fb;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #111116; --fg: #ececf1; --muted: #a3a3b1; --line: #2a2a34; --accent: #8c97ff; --soft: #1a1a22;
  }
}
:root[data-theme="dark"] {
  --bg: #111116; --fg: #ececf1; --muted: #a3a3b1; --line: #2a2a34; --accent: #8c97ff; --soft: #1a1a22;
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--fg);
  font: 16px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif; }
main { max-width: 720px; margin: 0 auto; padding: 56px 16px 72px; }
header.site { display: flex; justify-content: space-between; align-items: center; gap: 16px; flex-wrap: wrap;
  max-width: 720px; margin: 0 auto; padding: 20px 16px 0; font-size: 15px; }
header.site a { color: var(--fg); text-decoration: none; font-weight: 600; }
header.site nav { display: flex; gap: 16px; flex-wrap: wrap; }
header.site nav a { color: var(--muted); font-weight: 400; }
h1 { font-size: 34px; line-height: 1.15; letter-spacing: -0.01em; margin: 0 0 14px; }
h2 { font-size: 21px; margin: 40px 0 10px; }
h3 { font-size: 17px; margin: 24px 0 6px; }
p.lead { font-size: 19px; color: var(--muted); margin: 0 0 28px; }
a { color: var(--accent); }
.button { display: inline-block; background: var(--accent); color: #fff; text-decoration: none;
  padding: 12px 20px; border-radius: 10px; font-weight: 600; }
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 14px; margin: 28px 0; }
.card { border: 1px solid var(--line); border-radius: 12px; padding: 16px; background: var(--soft); }
.card h3 { margin-top: 0; }
.card p { margin: 0; color: var(--muted); font-size: 15px; }
table { width: 100%; border-collapse: collapse; font-size: 15px; margin: 12px 0 24px; }
th, td { text-align: left; padding: 9px 8px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { color: var(--muted); font-weight: 600; }
ol li, ul li { margin: 6px 0; }
.note { color: var(--muted); font-size: 14px; }
footer.site { border-top: 1px solid var(--line); margin-top: 56px; padding-top: 20px; color: var(--muted); font-size: 14px; }
code { background: var(--soft); padding: 1px 5px; border-radius: 4px; font-size: 14px; }