:root {
    --primary: #1E3A8A;
    --secondary: #85C1E9;
    --accent: #FF9F40;
    --dark: #0A1F4D;
    --light: #F5F7FA;
    --text: #333333;
    --text-light: #666666;
    --transition: all 0.3s ease;
  }

  @font-face {
    font-family: 'Roboto';
    src: url('https://fonts.googleapis.com/css2?family=Roboto:wght@300;400;500;700&display=swap');
  }

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

  body {
    font-family: 'Roboto', sans-serif;
    color: var(--text);
    background: linear-gradient(135deg, var(--light) 0%, #E6E9F0 100%);
    line-height: 1.6;
    overflow-x: hidden;
  }

  .container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
  }

  .header {
    background: linear-gradient(90deg, var(--primary) 0%, var(--dark) 100%);
    color: white;
    padding: 2rem 0;
    text-align: center;
    position: relative;
    overflow: hidden;
    margin-bottom: 3rem;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
  }

  .header::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('https://images.gptkong.com/demo/sample1.png') center/cover no-repeat;
    opacity: 0.1;
    z-index: 0;
  }

  .header-content {
    position: relative;
    z-index: 1;
  }

  .header h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
  }

  .header p {
    font-size: 1.1rem;
    max-width: 800px;
    margin: 0 auto;
    opacity: 0.9;
  }

  .notice {
    background-color: var(--accent);
    color: white;
    padding: 1rem;
    text-align: center;
    font-weight: 500;
    margin-bottom: 2rem;
    border-radius: 4px;
    box-shadow: 0 2px 10px rgba(255, 159, 64, 0.3);
  }

  .main-content {
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: 2rem;
    margin-bottom: 3rem;
  }

  @media (max-width: 768px) {
    .main-content {
      grid-template-columns: 1fr;
    }
  }

  .sidebar {
    background: white;
    border-radius: 8px;
    padding: 1.5rem;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
    position: sticky;
    top: 20px;
    height: fit-content;
  }

  .sidebar-title {
    color: var(--primary);
    font-size: 1.2rem;
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--secondary);
  }

  .nav-links {
    list-style: none;
  }

  .nav-links li {
    margin-bottom: 0.8rem;
  }

  .nav-links a {
    color: var(--text);
    text-decoration: none;
    display: block;
    padding: 0.5rem;
    border-radius: 4px;
    transition: var(--transition);
    position: relative;
  }

  .nav-links a::before {
    content: "";
    position: absolute;
    left: 0;
    top: 0;
    width: 3px;
    height: 100%;
    background-color: var(--accent);
    transform: scaleY(0);
    transition: var(--transition);
  }

  .nav-links a:hover {
    background-color: rgba(133, 193, 233, 0.1);
    color: var(--primary);
  }

  .nav-links a:hover::before {
    transform: scaleY(1);
  }

  .content {
    background: white;
    border-radius: 8px;
    padding: 2rem;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
  }

  article h2 {
    color: var(--primary);
    font-size: 1.8rem;
    margin: 2rem 0 1rem;
    position: relative;
    padding-bottom: 0.5rem;
  }

  article h2::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, var(--accent) 0%, var(--secondary) 100%);
  }

  article h3 {
    color: var(--dark);
    font-size: 1.4rem;
    margin: 1.5rem 0 0.8rem;
  }

  article p {
    margin-bottom: 1.2rem;
    font-size: 1.05rem;
    line-height: 1.7;
  }

  pre {
    background: #f8f9fa;
    border-radius: 6px;
    padding: 1.2rem;
    margin: 1.5rem 0;
    overflow-x: auto;
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.95rem;
    border-left: 4px solid var(--accent);
    box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.05);
  }

  code {
    color: #d63384;
    background-color: rgba(214, 51, 132, 0.1);
    padding: 0.2rem 0.4rem;
    border-radius: 3px;
    font-size: 0.9rem;
  }

  .image-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
  }

  .image-card {
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    transition: var(--transition);
    position: relative;
  }

  .image-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
  }

  .image-card img {
    width: 100%;
    height: auto;
    display: block;
    transition: var(--transition);
  }

  .image-card:hover img {
    transform: scale(1.03);
  }

  .image-caption {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background: linear-gradient(to top, rgba(0, 0, 0, 0.7) 0%, transparent 100%);
    color: white;
    padding: 1.5rem 1rem 1rem;
    opacity: 0;
    transition: var(--transition);
  }

  .image-card:hover .image-caption {
    opacity: 1;
  }

  .example-section {
    background: linear-gradient(135deg, rgba(30, 58, 138, 0.03) 0%, rgba(133, 193, 233, 0.03) 100%);
    border-radius: 8px;
    padding: 2rem;
    margin: 2rem 0;
    border: 1px solid rgba(133, 193, 233, 0.3);
  }

  .example-title {
    color: var(--primary);
    font-size: 1.3rem;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
  }

  .example-title::before {
    content: "";
    display: inline-block;
    width: 8px;
    height: 8px;
    background-color: var(--accent);
    border-radius: 50%;
    margin-right: 10px;
  }

  .example-content {
    color: var(--text-light);
    font-size: 0.95rem;
  }

  .footer {
    background: linear-gradient(90deg, var(--dark) 0%, var(--primary) 100%);
    color: white;
    padding: 2rem 0;
    text-align: center;
    margin-top: 3rem;
  }

  .footer p {
    opacity: 0.8;
  }

  /* Animations */
  @keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
  }

  .fade-in {
    animation: fadeIn 0.6s ease-out forwards;
  }

  .delay-1 { animation-delay: 0.2s; }
  .delay-2 { animation-delay: 0.4s; }
  .delay-3 { animation-delay: 0.6s; }

  /* Responsive adjustments */
  @media (max-width: 992px) {
    .header h1 {
      font-size: 2rem;
    }
  }

  @media (max-width: 768px) {
    .header {
      padding: 1.5rem 0;
    }
    
    .header h1 {
      font-size: 1.8rem;
    }
    
    article h2 {
      font-size: 1.5rem;
    }
    
    article h3 {
      font-size: 1.2rem;
    }
  }

  @media (max-width: 576px) {
    .container {
      padding: 0 15px;
    }
    
    .content, .sidebar {
      padding: 1.2rem;
    }
    
    pre {
      padding: 0.8rem;
      font-size: 0.85rem;
    }
  }