:root { color-scheme: light dark; --bg:#f7f8fc; --fg:#1c2340; --muted:#5a6488; --card:#ffffff; --line:#e3e7f5; --accent:#3b5bdb; }
@media (prefers-color-scheme: dark) { :root { --bg:#12172b; --fg:#eef1ff; --muted:#a8b2d8; --card:#1a2140; --line:#2b3358; --accent:#8ea2ff; } }
* { box-sizing: border-box; }
body { margin:0; background:var(--bg); color:var(--fg); font:16px/1.65 -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif; }
.wrap { max-width: 760px; margin: 0 auto; padding: 32px 20px 64px; }
header { display:flex; align-items:center; gap:12px; margin-bottom: 28px; }
header .mark { width:44px; height:44px; border-radius:12px; background:var(--accent); display:grid; place-items:center; color:#fff; font-weight:800; font-size:22px; }
h1 { font-size: 28px; margin: 0 0 6px; }
h2 { font-size: 19px; margin: 30px 0 10px; }
p, li { color: var(--fg); }
.lead { color: var(--muted); margin-top: 0; }
.card { background:var(--card); border:1px solid var(--line); border-radius:14px; padding:20px 22px; }
nav a { color: var(--accent); text-decoration: none; margin-right: 14px; font-weight:600; }
nav a:hover { text-decoration: underline; }
footer { margin-top: 34px; color: var(--muted); font-size: 14px; }
code { background: rgba(127,127,127,.14); padding: 1px 6px; border-radius: 6px; }
hr { border:0; border-top:1px solid var(--line); margin: 28px 0; }