:root{--bg:#f3fbf7;--ink:#1d2f3a;--muted:#5a6d77;--accent:#1f7f78;--card:#ffffff}
@media (prefers-color-scheme:dark){:root{--bg:#10202a;--ink:#e8f3f1;--muted:#a3b6bd;--accent:#6fd6c6;--card:#172c38}}
*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);font:17px/1.6 -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif}
main{max-width:720px;margin:0 auto;padding:32px 16px 64px}h1{font-size:2rem;margin:0 0 4px}h2{font-size:1.15rem;margin:28px 0 6px}
.card{background:var(--card);border-radius:16px;padding:20px 22px;box-shadow:0 2px 10px rgba(0,0,0,.06)}a{color:var(--accent)}.muted{color:var(--muted)}
nav{display:flex;gap:16px;margin-bottom:24px}