/* Simple modern responsive styling */
    :root{
      --bg: #f8fafc;
      --card: #ffffff;
      --muted: #6b7280;
      --accent: #16a34a; /* green */
      --max-width: 900px;
      --radius: 10px;
      --mono: ui-monospace, SFMono-Regular, Menlo, Monaco, "Roboto Mono", "Segoe UI Mono", monospace;
    }
    html,body{height:100%; margin:0; font-family: Inter, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial; background:var(--bg); color:#0f172a;}
    .container{max-width:var(--max-width); margin:36px auto; padding:28px;}
    .card{background:var(--card); border-radius:var(--radius); box-shadow: 0 6px 24px rgba(15,23,42,0.06); padding:28px; border:1px solid rgba(2,6,23,0.04);}
    header{display:flex;align-items:center;gap:14px;margin-bottom:18px;}
    .logo{
      width:56px;height:56px;border-radius:12px;display:inline-flex;align-items:center;justify-content:center;background:linear-gradient(135deg,var(--accent),#84cc16);
      color:white;font-weight:700;font-family:var(--mono);font-size:18px;
    }
    h1{font-size:22px;margin:0 0 6px 0;}
    .subtitle{color:var(--muted); font-size:14px; margin:0 0 20px 0;}
    h2{font-size:16px;margin-top:22px;margin-bottom:8px;}
    p, ul{line-height:1.55;color:#0b1220;margin:0 0 12px 0;}
    ul{padding-left:20px;}
    li{margin-bottom:8px;}
    .small{font-size:13px;color:var(--muted);}
    .accent{color:var(--accent);font-weight:600;}
    .grid{display:grid;grid-template-columns:1fr;gap:16px;}
    @media(min-width:720px){ .grid{grid-template-columns:1fr 300px;} .toc{position:sticky; top:24px; height:max-content; border-left:1px dashed #e6eef2; padding-left:18px} }
    .toc a{display:block;padding:6px 0;color:var(--muted);text-decoration:none;}
    .toc a:hover{color:#000;}
    .footer{margin-top:26px;padding-top:16px;border-top:1px solid #eef3f7;color:var(--muted);font-size:13px;}
    .cta{display:inline-block;background:var(--accent);color:white;padding:8px 12px;border-radius:8px;text-decoration:none;font-weight:600;}
    code{background:#f1f5f9;padding:3px 6px;border-radius:6px;font-family:var(--mono);font-size:13px;}