body {font-family: Arial, sans-serif; line-height: 1.8; margin: 40px; color: #222;}
  h1, h2, h3 {color: #003366;}
  h1 {font-size: 28px; border-bottom: 2px solid #ccc; padding-bottom: 10px;}
  h2 {margin-top: 40px;}
  a {color: #0066cc; text-decoration: none;}
  a:hover {text-decoration: underline;}
  .toc {background: #f5f5f5; padding: 20px; border-radius: 10px; margin-bottom: 30px;}
  .toc h2 {margin-top: 0;}
  img {display: block; margin: 20px auto; max-width: 100%; border-radius: 10px;}