:root {
  --ground: #EDF0F3; --surface: #FFFFFF; --ink: #1B2430; --muted: #5E6B7A; --hairline: #D5DBE2; --accent: #0072B2;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root { --ground: #14181D; --surface: #1E242B; --ink: #E9EDF1; --muted: #98A4B1; --hairline: #2C343D; --accent: #56B4E9; }
}
* { box-sizing: border-box; }
body {
  margin: 0; background: var(--ground); color: var(--ink);
  font: 17px/1.55 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
main { max-width: 42rem; margin: 0 auto; padding: 32px 16px 64px; }
header { margin-bottom: 24px; }
h1 { font-size: 1.9rem; line-height: 1.2; margin: 0 0 6px; }
h2 { font-size: 1.15rem; margin: 32px 0 8px; }
p, li { margin: 0 0 12px; }
.lede { color: var(--muted); font-size: 1.05rem; }
.card { background: var(--surface); border: 1px solid var(--hairline); border-radius: 14px; padding: 16px 18px; margin: 16px 0; }
a { color: var(--accent); }
nav { display: flex; gap: 16px; margin-bottom: 24px; font-size: 0.95rem; }
footer { color: var(--muted); font-size: 0.9rem; margin-top: 40px; border-top: 1px solid var(--hairline); padding-top: 16px; }