body {font-family: Arial, sans-serif; line-height:1.6; color:#222; margin:0 auto; max-width:900px; padding:20px;}
    h1 {font-size:28px; color:#003366; margin-bottom:10px;}
    h2 {font-size:22px; color:#003366; margin-top:40px;}
    h3 {font-size:18px; color:#003366; margin-top:30px;}
    a {color:#0066cc; text-decoration:none;}
    a:hover {text-decoration:underline;}
    .toc {background:#f5f5f5; border-left:4px solid #007bff; padding:15px; margin-bottom:30px;}
    img {max-width:100%; height:auto; display:block; margin:20px 0;}