:root{--bg:#fafaf7;--fg:#16181d;--mut:#5b6170;--ac:#0b5fff;--card:#fff;--bd:#e3e4df}
@media (prefers-color-scheme:dark){:root{--bg:#101216;--fg:#eceef2;--mut:#9aa1b0;--ac:#6ea0ff;--card:#171a20;--bd:#272b34}}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--fg);font:17px/1.6 system-ui,-apple-system,"Segoe UI",sans-serif}
main{max-width:46rem;margin:0 auto;padding:2.5rem 1.25rem 4rem}
nav{display:flex;justify-content:space-between;color:var(--mut);font-size:.9rem;margin-bottom:2.5rem}
a{color:var(--ac)}
h1{font-size:2.2rem;line-height:1.15;margin:.2rem 0 .8rem}
h2{font-size:1.15rem;margin:2.2rem 0 .6rem}
.lead{font-size:1.2rem;color:var(--mut)}
ol,ul{padding-left:1.2rem}li{margin:.5rem 0}
.card{background:var(--card);border:1px solid var(--bd);border-radius:10px;padding:1rem 1.2rem}
footer{margin-top:3rem;color:var(--mut);font-size:.85rem}