:root { --fg:#222; --bg:#fafafa; --muted:#666; --accent:#3a5a78; }
* { box-sizing: border-box; }
body {
  margin:0 auto; max-width:42rem; padding:3rem 1.25rem;
  font:16px/1.6 -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  color:var(--fg); background:var(--bg);
}
header h1 { margin:0; font-size:2rem; letter-spacing:.02em; }
.tagline { margin:.25rem 0 1rem; color:var(--muted); }
nav { border-bottom:1px solid #e5e5e5; padding-bottom:1rem; margin-bottom:2rem; }
nav a, main a { color:var(--accent); text-decoration:none; }
nav a:hover, main a:hover { text-decoration:underline; }
section { margin-bottom:2rem; }
h2 { font-size:1.1rem; margin:0 0 .5rem; }
ul { padding-left:1.2rem; }
footer { color:var(--muted); font-size:.85rem; border-top:1px solid #e5e5e5; padding-top:1rem; margin-top:2rem; }