:root { --bg: #ffffff; --fg: #1d1d1f; --sub: #6e6e73; --line: #d2d2d7; --link: #0066cc; }
@media (prefers-color-scheme: dark) {
  :root { --bg: #000000; --fg: #f5f5f7; --sub: #a1a1a6; --line: #38383a; --link: #2997ff; }
}
body { margin: 0; background: var(--bg); color: var(--fg); font: 17px/1.6 -apple-system, BlinkMacSystemFont, "Apple SD Gothic Neo", "Hiragino Sans", sans-serif; }
main { max-width: 640px; margin: 0 auto; padding: 48px 16px 96px; }
nav { font-size: 15px; color: var(--sub); }
section { padding-top: 32px; }
section + section { margin-top: 48px; border-top: 1px solid var(--line); }
h1 { margin: 0 0 8px; font-size: 32px; letter-spacing: -0.5px; }
h2 { margin: 32px 0 4px; font-size: 19px; }
p { margin: 0 0 8px; }
.meta { color: var(--sub); font-size: 15px; }
a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }