:root { --brand: #2F5BD3; --ink: #1c1c1e; --sub: #6b6b70; --bg: #ffffff; --card: #f4f6fb; }
@media (prefers-color-scheme: dark) { :root { --ink: #f2f2f7; --sub: #a1a1a8; --bg: #0b0b0f; --card: #17181e; } }
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 17px/1.7 -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue", sans-serif; }
main { max-width: 720px; margin: 0 auto; padding: 48px 20px 80px; }
h1 { font-size: 32px; line-height: 1.3; margin: 0 0 8px; }
h2 { font-size: 21px; margin: 36px 0 8px; }
p, li { color: var(--ink); }
.sub { color: var(--sub); }
.card { background: var(--card); border-radius: 16px; padding: 16px 20px; margin: 16px 0; }
a { color: var(--brand); }
footer { margin-top: 48px; color: var(--sub); font-size: 14px; }