/* ========== THEME ========== */
    :root{
      --brand:#0F212C;
      --brand-2:#113447;
      --accent:#12B886;
      --ink:#0f212c;
      --muted:#5a6c7a;
      --bg:#f6f8fb;
      --soft:#ffffff;
      --line:#e6eef3;
      --radius:16px;
      --shadow:0 14px 40px rgba(15,33,44,.10);
      --ring:0 0 0 3px rgba(46,116,255,.25);
    }
    @media (prefers-color-scheme: dark){
      :root{
        --ink:#eaf2f9;
        --muted:#9db3c5;
        --bg:#0A141C;
        --soft:#0F212C;
        --line:#163042;
        --shadow:0 18px 50px rgba(0,0,0,.45);
      }
    }

    /* ========== BASE ========== */
    *{box-sizing:border-box}
    html,body{margin:0}
    html{scroll-behavior:smooth}
    body{
      font-family:Inter,ui-sans-serif,system-ui,Segoe UI,Roboto,Arial,sans-serif;
      background:var(--bg);
      color:var(--ink);
      line-height:1.6;
    }
    a{color:inherit}
    .container{max-width:1100px;margin:0 auto;padding:0 20px}

    /* ========== HERO ========== */
    .hero{
      background:
        radial-gradient(1200px 350px at 10% -10%, rgba(255,255,255,.15), transparent 60%),
        linear-gradient(120deg, var(--brand), var(--brand-2));
      color:#fff;
      padding:64px 0 48px;
      position:relative;
      overflow:hidden;
    }
    .hero .eyebrow{
      display:inline-flex;align-items:center;gap:8px;
      background:rgba(255,255,255,.12);
      border:1px solid rgba(255,255,255,.22);
      padding:6px 10px;border-radius:999px;font-weight:700;font-size:12px;backdrop-filter:saturate(120%) blur(2px)
    }
    .hero h1{font-size:34px;line-height:1.15;margin:12px 0 6px}
    .hero .lead{opacity:.92;max-width:780px;margin:0 0 8px}
    .meta{opacity:.75;font-size:14px}

    /* ========== LAYOUT ========== */
    main{margin:-28px 0 50px}
    .layout{
      display:grid;gap:18px;
      grid-template-columns: minmax(0,1.25fr) minmax(0,.75fr);
    }
    @media (max-width:960px){.layout{grid-template-columns:1fr}}
    .card{
      background:var(--soft);border:1px solid var(--line);border-radius:var(--radius);
      box-shadow:var(--shadow); padding:20px;
    }
    .section + .section{margin-top:16px}

    /* ========== TOC (Right) ========== */
    .side{position:relative}
    .sticky{position:sticky; top:14px; display:flex; flex-direction:column; gap:14px;}
    .toc{padding:14px}
    .toc h3{margin:0 0 8px;font-size:14px;color:var(--muted);font-weight:700}
    .toc a{
      display:flex;align-items:center;gap:10px;
      padding:10px 12px;border-radius:12px;border:1px solid var(--line);
      text-decoration:none;font-weight:600;
    }
    .toc a:hover{background:rgba(18,184,134,.08)}
    .toc nav{display:grid;gap:10px}

    /* ========== CONTENT ========== */
    .section h2{font-size:22px;margin:0 0 8px}
    .list-tight{padding-left:18px}
    .list-tight li{margin:6px 0}
    .btn{
      display:inline-flex;align-items:center;gap:8px;
      border-radius:999px;padding:10px 14px;font-weight:700;
      border:1px solid #d9e4ee;background:#fff;cursor:pointer;
    }
    .btn:focus-visible{outline:none;box-shadow:var(--ring)}
    .btn-ghost{background:transparent}
    @media (prefers-color-scheme: dark){
      .btn{background:#0f2836;border-color:#1a3a4e;color:#cfe3f7}
    }

    /* Tables (if needed) */
    .table-wrap{border:1px solid var(--line);border-radius:14px;overflow:hidden;background:#fff}
    @media (prefers-color-scheme: dark){.table-wrap{background:#0e2330}}
    table{width:100%;border-collapse:collapse}
    th,td{padding:12px;border-bottom:1px solid var(--line);vertical-align:top}
    th{background:#f3f7fb;text-align:left;font-weight:700}
    @media (prefers-color-scheme: dark){th{background:#122a39}}
    tr:nth-child(even) td{background:rgba(17,52,71,.03)}
    @media (prefers-color-scheme: dark){tr:nth-child(even) td{background:rgba(255,255,255,.03)}}

    /* Print */
    @media print{
      .hero,.side,.toc,.btn{display:none !important}
      body{background:#fff;color:#000}
      main{margin:0}
      a::after{content:" (" attr(href) ")";font-size:12px}
    }

    .sr-only{position:absolute !important; width:1px;height:1px; padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);border:0}