:root{
      --bg: #0b1220;
      --panel: rgba(255,255,255,.06);
      --panel2: rgba(255,255,255,.09);
      --text: rgba(255,255,255,.92);
      --muted: rgba(255,255,255,.72);
      --faint: rgba(255,255,255,.55);
      --border: rgba(255,255,255,.14);
      --shadow: 0 12px 30px rgba(0,0,0,.35);
      --accent: #7c3aed; /* purple */
      --accent2: #a78bfa;
      --good: #22c55e;
      --warn: #fbbf24;
      --danger: #fb7185;
      --radius: 16px;
      --radius2: 22px;
      --max: 1120px;
      --pad: clamp(16px, 2.2vw, 26px);
      --gap: clamp(12px, 1.8vw, 20px);
      --font: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji","Segoe UI Emoji";
    }

    @media (prefers-color-scheme: light){
      :root{
        --bg: #f6f7fb;
        --panel: rgba(10,15,30,.045);
        --panel2: rgba(10,15,30,.06);
        --text: rgba(10,15,30,.92);
        --muted: rgba(10,15,30,.72);
        --faint: rgba(10,15,30,.56);
        --border: rgba(10,15,30,.14);
        --shadow: 0 12px 30px rgba(10,15,30,.10);
        --accent: #6d28d9;
        --accent2: #8b5cf6;
      }
    }

    *{box-sizing:border-box}
    html{scroll-behavior:smooth}
    body{
      margin:0;
      font-family: var(--font);
      background:
        radial-gradient(1200px 600px at 15% -10%, rgba(124,58,237,.35), transparent 60%),
        radial-gradient(900px 500px at 100% 0%, rgba(167,139,250,.28), transparent 60%),
        radial-gradient(900px 600px at 40% 120%, rgba(34,197,94,.18), transparent 60%),
        var(--bg);
      color: var(--text);
      line-height: 1.55;
      -webkit-font-smoothing: antialiased;
      text-rendering: optimizeLegibility;
    }

    a{color:inherit}
    .wrap{max-width: var(--max); margin:0 auto; padding: 0 var(--pad);}
    .skip{
      position:absolute; left:-999px; top:10px;
      background: var(--text); color: var(--bg);
      padding: 10px 12px; border-radius: 10px;
    }
    .skip:focus{left:10px; z-index:9999}

    header{
      position: sticky;
      top: 0;
      z-index: 50;
      backdrop-filter: blur(10px);
      background: linear-gradient(to bottom, rgba(0,0,0,.35), rgba(0,0,0,.18));
      border-bottom: 1px solid var(--border);
    }
    @media (prefers-color-scheme: light){
      header{background: linear-gradient(to bottom, rgba(255,255,255,.85), rgba(255,255,255,.60));}
    }

    .topbar{
      display:flex;
      align-items:center;
      justify-content: space-between;
      gap: 14px;
      padding: 12px 0;
    }
    .brand{
      display:flex; align-items:center; gap:10px;
      text-decoration:none;
      min-width: 210px;
    }
    .logo{
      width:34px; height:34px; border-radius: 12px;
      background:
        radial-gradient(circle at 30% 20%, rgba(255,255,255,.35), transparent 55%),
        linear-gradient(135deg, var(--accent), var(--accent2));
      box-shadow: 0 8px 18px rgba(124,58,237,.25);
      border: 1px solid rgba(255,255,255,.18);
    }
    .brand strong{font-size: 14px; letter-spacing: .2px}
    .brand span{display:block; font-size:12px; color: var(--muted); margin-top: 2px}

    nav{
      display:flex; flex-wrap:wrap;
      gap: 10px;
      justify-content: flex-end;
    }
    nav a{
      font-size: 13px;
      text-decoration:none;
      color: var(--muted);
      padding: 8px 10px;
      border-radius: 10px;
      border: 1px solid transparent;
      transition: .15s ease;
      white-space: nowrap;
    }
    nav a:hover{
      color: var(--text);
      border-color: var(--border);
      background: var(--panel);
    }
    .cta-mini{
      color: #fff !important;
      background: linear-gradient(135deg, var(--accent), var(--accent2));
      border-color: rgba(255,255,255,.16) !important;
      box-shadow: 0 10px 22px rgba(124,58,237,.22);
    }
    .cta-mini:hover{filter: brightness(1.02)}

    main{padding: 22px 0 70px}

    .hero{
      padding: 28px 0 6px;
    }
    .kicker{
      display:inline-flex; align-items:center; gap:8px;
      padding: 8px 12px;
      border: 1px solid var(--border);
      background: var(--panel);
      border-radius: 999px;
      color: var(--muted);
      font-size: 13px;
    }
    .dot{
      width:9px; height:9px; border-radius: 999px;
      background: radial-gradient(circle at 35% 35%, #fff, rgba(255,255,255,.2) 35%), var(--good);
      box-shadow: 0 0 0 4px rgba(34,197,94,.10);
    }
    h1{
      margin: 14px 0 10px;
      font-size: clamp(28px, 4.2vw, 46px);
      line-height: 1.12;
      letter-spacing: -0.5px;
    }
    .lead{
      max-width: 75ch;
      color: var(--muted);
      font-size: clamp(15px, 1.45vw, 18px);
      margin: 0 0 18px;
    }
    .hero-grid{
      display:grid;
      grid-template-columns: 1.15fr .85fr;
      gap: var(--gap);
      align-items: start;
      margin-top: 16px;
    }
    @media (max-width: 980px){
      .hero-grid{grid-template-columns: 1fr}
      .brand{min-width:auto}
    }

    .card{
      background: linear-gradient(180deg, var(--panel), transparent 140%);
      border: 1px solid var(--border);
      border-radius: var(--radius2);
      box-shadow: var(--shadow);
    }
    .card-inner{padding: var(--pad)}
    .pill-row{display:flex; flex-wrap:wrap; gap:10px; margin-top: 14px}
    .pill{
      padding: 8px 10px;
      border-radius: 999px;
      border: 1px solid var(--border);
      background: var(--panel);
      color: var(--muted);
      font-size: 13px;
      display:inline-flex; gap:8px; align-items:center;
    }
    .pill b{color: var(--text); font-weight: 650}
    .actions{
      display:flex; flex-wrap:wrap; gap: 12px;
      margin-top: 18px;
    }
    .btn{
      display:inline-flex; align-items:center; justify-content:center;
      gap: 10px;
      padding: 12px 14px;
      border-radius: 14px;
      border: 1px solid var(--border);
      background: var(--panel);
      color: var(--text);
      text-decoration:none;
      font-size: 14px;
      transition: .15s ease;
      min-height: 44px;
    }
    .btn:hover{transform: translateY(-1px); background: var(--panel2)}
    .btn.primary{
      background: linear-gradient(135deg, var(--accent), var(--accent2));
      border-color: rgba(255,255,255,.16);
      color: #fff;
      box-shadow: 0 12px 26px rgba(124,58,237,.25);
    }
    .btn.primary:hover{filter: brightness(1.02)}
    .btn .icon{
      width: 18px; height: 18px; display:inline-block;
      border-radius: 6px;
      background: rgba(255,255,255,.22);
    }
    .note{
      color: var(--faint);
      font-size: 12.5px;
      margin-top: 12px;
    }

    .sidebox h2{
      margin:0 0 10px;
      font-size: 16px;
      letter-spacing: .2px;
    }
    .sidebox p{margin:0 0 12px; color: var(--muted); font-size: 14px}
    .sidebox ul{margin:0; padding-left: 18px; color: var(--muted); font-size: 14px}
    .sidebox li{margin: 8px 0}

    section{padding: 22px 0}
    .section-title{
      display:flex; align-items:baseline; justify-content:space-between;
      gap: 14px;
      margin: 0 0 10px;
    }
    .section-title h2{
      margin:0;
      font-size: clamp(18px, 2.2vw, 26px);
      letter-spacing: -0.2px;
    }
    .section-title .tag{
      border: 1px solid var(--border);
      background: var(--panel);
      padding: 7px 10px;
      border-radius: 999px;
      font-size: 12px;
      color: var(--muted);
      white-space: nowrap;
    }
    .prose{
      max-width: 92ch;
      color: var(--muted);
      font-size: 15.5px;
    }
    .prose p{margin: 10px 0}
    .prose strong{color: var(--text)}
    .grid{
      display:grid;
      grid-template-columns: repeat(12, 1fr);
      gap: var(--gap);
      margin-top: 14px;
    }
    .col-6{grid-column: span 6}
    .col-7{grid-column: span 7}
    .col-5{grid-column: span 5}
    .col-4{grid-column: span 4}
    .col-12{grid-column: span 12}
    @media (max-width: 980px){
      .col-6,.col-7,.col-5,.col-4{grid-column: span 12}
    }

    .mini{
      border-radius: var(--radius2);
      border: 1px solid var(--border);
      background: linear-gradient(180deg, var(--panel), transparent 140%);
      padding: var(--pad);
      box-shadow: var(--shadow);
    }
    .mini h3{
      margin: 0 0 10px;
      font-size: 16px;
      letter-spacing: .2px;
    }
    .mini p{margin: 0 0 10px; color: var(--muted); font-size: 14.5px}
    .mini ul{margin: 0; padding-left: 18px; color: var(--muted); font-size: 14.5px}
    .mini li{margin: 7px 0}

    .callout{
      border-radius: var(--radius2);
      border: 1px solid rgba(124,58,237,.28);
      background: radial-gradient(800px 280px at 20% 0%, rgba(124,58,237,.22), transparent 60%),
                  linear-gradient(180deg, rgba(124,58,237,.12), transparent 110%);
      padding: var(--pad);
      box-shadow: var(--shadow);
    }
    .callout h3{margin:0 0 10px; font-size: 17px}
    .callout p{margin:0 0 12px; color: var(--muted)}
    .callout .actions{margin-top: 12px}

    /* MCQ - CSS-only reveal */
    .quiz{
      display:flex; flex-direction:column;
      gap: 14px;
      margin-top: 14px;
    }
    .q{
      border: 1px solid var(--border);
      background: linear-gradient(180deg, var(--panel), transparent 140%);
      border-radius: var(--radius2);
      padding: var(--pad);
      box-shadow: var(--shadow);
    }
    .q .meta{
      display:flex; align-items:center; justify-content:space-between; gap: 10px;
      margin-bottom: 10px;
    }
    .q .meta b{font-size: 13px; letter-spacing:.2px}
    .q .meta span{font-size: 12px; color: var(--muted); border: 1px solid var(--border); background: var(--panel); padding: 6px 10px; border-radius: 999px}
    .q h3{margin:0 0 10px; font-size: 16px}
    .choices{margin: 0; padding-left: 18px; color: var(--muted)}
    .choices li{margin: 8px 0}

    .reveal{
      margin-top: 12px;
      border-top: 1px dashed var(--border);
      padding-top: 12px;
    }
    .reveal input{position:absolute; opacity:0; pointer-events:none}
    .reveal label{
      display:inline-flex; align-items:center; gap: 10px;
      cursor:pointer;
      user-select:none;
      font-size: 13.5px;
      padding: 10px 12px;
      border-radius: 12px;
      border: 1px solid var(--border);
      background: var(--panel);
      color: var(--text);
      transition: .15s ease;
    }
    .reveal label:hover{background: var(--panel2)}
    .answer{
      margin-top: 12px;
      display:none;
      border-left: 3px solid var(--accent);
      padding: 10px 12px;
      border-radius: 12px;
      background: var(--panel);
      color: var(--muted);
      font-size: 14px;
    }
    .reveal input:checked ~ .answer{display:block}
    .answer strong{color: var(--text)}

    /* FAQ */
    details{
      border: 1px solid var(--border);
      background: linear-gradient(180deg, var(--panel), transparent 140%);
      border-radius: var(--radius2);
      padding: 14px var(--pad);
      box-shadow: var(--shadow);
    }
    details + details{margin-top: 12px}
    summary{
      cursor:pointer;
      list-style:none;
      font-weight: 650;
      color: var(--text);
      font-size: 15px;
    }
    summary::-webkit-details-marker{display:none}
    details p{margin: 10px 0 0; color: var(--muted)}
    details ul{margin: 10px 0 0; color: var(--muted); padding-left: 18px}

    footer{
      padding: 26px 0 40px;
      border-top: 1px solid var(--border);
      color: var(--faint);
    }
    .foot{
      display:flex; flex-wrap:wrap; align-items:flex-start; justify-content:space-between;
      gap: 16px;
    }
    .foot a{color: var(--muted); text-decoration:none}
    .foot a:hover{text-decoration:underline}
    .small{font-size: 12.5px; max-width: 95ch}
    .hr{height:1px; background: var(--border); margin: 18px 0}