:root{
      --bg: #f7f7f8;
      --card: #ffffff;
      --text: #0f172a;
      --muted: #515e75;
      --border: #e5e7eb;
      --primary: #111827;
      --accent: #2563eb;
      --ring: rgba(37,99,235,.25);
      --maxw: 920px;
    }
    *{box-sizing: border-box}
    html,body{height:100%}
    body{margin:0;font-family:'Inter',system-ui,-apple-system,"Segoe UI",Roboto,Ubuntu,"Helvetica Neue",Arial,sans-serif;color:var(--text);background:linear-gradient(180deg,#fafafa,#f3f4f6)}

    /* NAVBAR */
    .navbar{position:sticky;top:0;width:100%;backdrop-filter:saturate(180%) blur(10px);background:rgba(255,255,255,0.7);border-bottom:1px solid var(--border);z-index:50}
    .nav-inner{max-width:var(--maxw);margin:0 auto;display:flex;align-items:center;justify-content:space-between;padding:14px 20px}
    .brand{display:inline-flex;align-items:center;gap:10px;text-decoration:none;color:inherit}
    .brand-logo{width:28px;height:28px;border-radius:8px;background:var(--primary);display:grid;place-items:center;color:#fff;font-size:14px;font-weight:700}
    .brand-name{font-weight:700;letter-spacing:-.01em}
    .nav-links{display:flex;gap:18px}
    .nav-links a{color:var(--muted);text-decoration:none;font-size:14px}
    .nav-links a:hover{color:var(--text)}

    /* WRAPPER */
    .wrapper{max-width:var(--maxw);margin:28px auto;padding:0 20px}

    /* HERO */
    .hero{background:var(--card);border:1px solid var(--border);border-radius:18px;padding:22px 20px;box-shadow:0 10px 30px rgba(2,6,23,.05)}
    .hero h1{margin:0 0 6px;font-size:28px;letter-spacing:-.02em}
    .hero p{margin:0;color:var(--muted);font-size:14px}

    /* TOC */
    .toc{margin:18px 0 12px;padding:14px 16px;border:1px dashed var(--border);border-radius:14px;background:#fff}
    .toc h3{margin:0 0 8px;font-size:14px;color:var(--muted)}
    .toc ol{margin:0;padding-left:16px;display:grid;gap:6px}
    .toc a{color:var(--accent);text-decoration:none}
    .toc a:hover{text-decoration:underline}

    /* SECTIONS */
    section.block{background:#fff;border:1px solid var(--border);border-radius:18px;padding:18px 20px;margin:14px 0;box-shadow:0 8px 24px rgba(2,6,23,.04)}
    section.block h2{margin:0 0 10px;font-size:20px}
    section.block p{margin:8px 0;color:#2e3340}
    section.block ul{margin:8px 0 8px 18px}
    code.code{background:#0f172a; color:#f8fafc; padding:2px 6px; border-radius:6px; font-size:12px}

    /* CALLOUT */
    .callout{border-left:4px solid var(--accent);background:#eef2ff;color:#1e293b;padding:12px 14px;border-radius:8px;margin:10px 0;font-size:13px}

    /* FOOTER */
    footer{margin:30px auto 40px;max-width:var(--maxw);padding:12px 20px;color:var(--muted);font-size:12px;display:flex;align-items:center;justify-content:space-between;border-top:1px solid var(--border)}
    .foot-links{display:flex;gap:14px}
    .foot-links a{color:var(--muted);text-decoration:none}
    .foot-links a:hover{color:var(--text)}

    /* PRINT */
    @media print{
      .navbar,footer{display:none}
      body{background:#fff}
      .wrapper{max-width:100%;margin:0;padding:0}
      section.block,.hero{box-shadow:none;border-color:#ccc}
      a{text-decoration:underline;color:#000}
    }