:root{
      --bg:#f7fbff;
      --white:#ffffff;
      --text:#1f2937;
      --muted:#6b7280;
      --line:#dbe7f3;
      --primary:#1f6fb2;
      --primary-dark:#15558a;
      --soft:#eaf4fc;
      --accent:#0f172a;
    }

    *{
      box-sizing:border-box;
      margin:0;
      padding:0;
    }

    body{
      font-family: Arial, Helvetica, sans-serif;
      background:var(--bg);
      color:var(--text);
      line-height:1.75;
    }

    a{
      color:var(--primary);
      text-decoration:none;
    }

    a:hover{
      text-decoration:underline;
    }

    .container{
      width:min(1100px, 92%);
      margin:0 auto;
    }

    .topbar{
      background:#ffffff;
      border-bottom:1px solid var(--line);
    }

    .topbar .container{
      padding:14px 0;
      font-size:14px;
      color:var(--muted);
    }

    .hero{
      padding:52px 0 28px;
    }

    .hero-card{
      background:linear-gradient(135deg, #ffffff 0%, #eef7ff 100%);
      border:1px solid var(--line);
      border-radius:18px;
      padding:42px 34px;
      box-shadow:0 10px 28px rgba(31,111,178,0.06);
    }

    .eyebrow{
      display:inline-block;
      font-size:13px;
      letter-spacing:.08em;
      text-transform:uppercase;
      color:var(--primary);
      font-weight:700;
      margin-bottom:14px;
    }

    h1{
      font-size:clamp(30px, 4.5vw, 48px);
      line-height:1.2;
      color:var(--accent);
      margin-bottom:16px;
    }

    .hero-desc{
      font-size:18px;
      color:var(--muted);
      max-width:850px;
    }

    .meta{
      display:flex;
      flex-wrap:wrap;
      gap:14px 20px;
      margin-top:22px;
      color:var(--muted);
      font-size:14px;
    }

    .layout{
      display:grid;
      grid-template-columns:minmax(0, 1fr) 320px;
      gap:34px;
      padding:24px 0 60px;
    }

    .article{
      min-width:0;
    }

    .sidebar{
      min-width:0;
    }

    .card{
      background:var(--white);
      border:1px solid var(--line);
      border-radius:18px;
      padding:28px;
      margin-bottom:24px;
      box-shadow:0 8px 22px rgba(15,23,42,0.04);
    }

    .article p{
      margin-bottom:18px;
      font-size:17px;
      color:#334155;
    }

    .article h2{
      font-size:30px;
      line-height:1.3;
      margin:34px 0 18px;
      color:#0f172a;
    }

    .article h3{
      font-size:22px;
      line-height:1.35;
      margin:24px 0 14px;
      color:#0f172a;
    }

    .article ul,
    .article ol{
      margin:0 0 20px 22px;
      color:#334155;
    }

    .article li{
      margin-bottom:10px;
      font-size:17px;
    }

    .highlight{
      background:var(--soft);
      border-left:4px solid var(--primary);
      padding:18px 18px;
      border-radius:10px;
      margin:20px 0 26px;
      color:#1e3a5f;
    }

    .table-wrap{
      overflow-x:auto;
      margin:22px 0 28px;
      border:1px solid var(--line);
      border-radius:14px;
      background:#fff;
    }

    table{
      width:100%;
      border-collapse:collapse;
      min-width:760px;
    }

    th, td{
      padding:15px 16px;
      border-bottom:1px solid var(--line);
      text-align:left;
      vertical-align:top;
      font-size:15px;
    }

    th{
      background:#edf6fd;
      color:#0f172a;
      font-weight:700;
    }

    tr:last-child td{
      border-bottom:none;
    }

    .toc h3,
    .sidebar h3{
      font-size:18px;
      margin-bottom:14px;
      color:#0f172a;
    }

    .toc ul,
    .sidebar ul{
      list-style:none;
      margin:0;
      padding:0;
    }

    .toc li,
    .sidebar li{
      margin-bottom:10px;
    }

    .toc a{
      color:#334155;
    }

    .cta-box{
      background:linear-gradient(135deg, #eaf4fc 0%, #ffffff 100%);
      border:1px solid var(--line);
      border-radius:18px;
      padding:28px;
      margin-top:30px;
    }

    .cta-box h3{
      margin-top:0;
      margin-bottom:12px;
    }

    .btn{
      display:inline-block;
      margin-top:10px;
      padding:12px 20px;
      background:var(--primary);
      color:#fff;
      border-radius:999px;
      font-weight:700;
      transition:all .2s ease;
    }

    .btn:hover{
      background:var(--primary-dark);
      text-decoration:none;
    }

    .faq-item{
      border-top:1px solid var(--line);
      padding:18px 0;
    }

    .faq-item:first-child{
      border-top:none;
      padding-top:0;
    }

    .faq-item h3{
      font-size:20px;
      margin-bottom:10px;
    }

    .author-box{
      display:flex;
      flex-direction:column;
      gap:10px;
      font-size:15px;
      color:var(--muted);
    }

    .tag-list{
      display:flex;
      flex-wrap:wrap;
      gap:10px;
      margin-top:8px;
    }

    .tag{
      display:inline-block;
      background:#eef6fc;
      border:1px solid #d7e9f7;
      color:#215d94;
      padding:8px 12px;
      border-radius:999px;
      font-size:13px;
    }

    .footer{
      border-top:1px solid var(--line);
      padding:26px 0 40px;
      color:var(--muted);
      font-size:14px;
    }

    @media (max-width: 980px){
      .layout{
        grid-template-columns:1fr;
      }

      .sidebar{
        order:-1;
      }
    }

    @media (max-width: 640px){
      .hero{
        padding:30px 0 18px;
      }

      .hero-card,
      .card{
        padding:22px 18px;
        border-radius:14px;
      }

      .article p,
      .article li{
        font-size:16px;
      }

      .article h2{
        font-size:25px;
      }

      .article h3{
        font-size:20px;
      }

      .hero-desc{
        font-size:16px;
      }
    }