:root{
  --ground:#F7F8F7; --surface:#FFFFFF; --ink:#22282A; --soft:#6F7A7D;
  --rule:#E5E9E8; --primary:#1F7A6B;
}
@media (prefers-color-scheme: dark){
  :root{ --ground:#171C1E; --surface:#212829; --ink:#ECF1F0; --soft:#9AA6A8;
         --rule:#323B3D; --primary:#6FD3BC; }
}
*{box-sizing:border-box}
body{margin:0;background:var(--ground);color:var(--ink);
     font:16px/1.65 -apple-system,BlinkMacSystemFont,"Segoe UI",Helvetica,Arial,sans-serif}
main{max-width:680px;margin:0 auto;padding:48px 20px 80px}
h1{font-size:1.9rem;line-height:1.2;margin:0 0 6px}
h2{font-size:1.1rem;margin:34px 0 8px}
p,ul{margin:0 0 14px}
ul{padding-left:20px}
a{color:var(--primary)}
.meta{color:var(--soft);font-size:.9rem;margin-bottom:28px;
      padding-bottom:20px;border-bottom:1px solid var(--rule)}
.lead{font-size:1.05rem}
nav{margin-top:40px;padding-top:20px;border-top:1px solid var(--rule);
    font-size:.9rem;color:var(--soft)}