:root{--bg:#fff;--fg:#1b1f24;--muted:#5b6570;--line:#e3e7eb;--accent:#0b6bcb;--card:#f5f7fa}
@media (prefers-color-scheme:dark){:root{--bg:#14171a;--fg:#e8ebee;--muted:#9aa5b0;--line:#2a3036;--accent:#6db3ff;--card:#1c2025}}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--fg);font:17px/1.6 -apple-system,system-ui,"Segoe UI",Roboto,sans-serif}
header,main,footer{max-width:46rem;margin:0 auto;padding:1rem 1rem}
header{display:flex;justify-content:space-between;align-items:baseline;flex-wrap:wrap;gap:.5rem;border-bottom:1px solid var(--line)}
header a.brand{font-weight:700;font-size:1.2rem;color:var(--fg);text-decoration:none}
nav a{margin-left:1rem;color:var(--accent)}
h1{font-size:1.9rem;line-height:1.2;margin:1.5rem 0 .5rem}
h2{font-size:1.3rem;margin:2rem 0 .5rem}
a{color:var(--accent)}
.card{background:var(--card);border:1px solid var(--line);border-radius:10px;padding:1rem 1.2rem;margin:1rem 0}
details{border-bottom:1px solid var(--line);padding:.7rem 0}
summary{cursor:pointer;font-weight:600}
footer{color:var(--muted);font-size:.9rem;border-top:1px solid var(--line);margin-top:2rem}