:root {
    --primary: #ff9800;
    --primary-light: #ffb74d;
    --primary-dark: #e68900;
    --secondary: #2196f3;
    --secondary-light: #64b5f6;
    --secondary-dark: #1976d2;
    --accent: #ff5722;
    --text: #333333;
    --text-light: #757575;
    --bg: #f5f5f7;
    --card-bg: #ffffff;
    --border-radius: 12px;
    --shadow: 0 4px 20px rgba(0,0,0,0.08);
    --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
  }

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

  body {
    font-family: 'Roboto', system-ui, -apple-system, sans-serif;
    line-height: 1.6;
    color: var(--text);
    background: var(--bg);
    overflow-x: hidden;
  }

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

  /* Header Styles */
  header {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    padding: 2rem 0;
    position: relative;
    overflow: hidden;
  }

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

  .header-content {
    position: relative;
    z-index: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    padding: 2rem;
  }

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

  .header-subtitle {
    font-size: 1.2rem;
    max-width: 700px;
    margin-bottom: 2rem;
    opacity: 0.9;
  }

  .reference-badge {
    background: rgba(255,255,255,0.2);
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 0.9rem;
    margin-top: 1rem;
  }

  /* Navigation */
  .main-nav {
    background: white;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
  }

  .nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
  }

  .nav-logo {
    font-weight: 700;
    color: var(--primary);
    text-decoration: none;
    font-size: 1.2rem;
  }

  .nav-menu {
    display: flex;
    list-style: none;
  }

  .nav-item {
    margin-left: 2rem;
  }

  .nav-link {
    color: var(--text);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    position: relative;
  }

  .nav-link:hover {
    color: var(--primary);
  }

  .nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary);
    transition: var(--transition);
  }

  .nav-link:hover::after {
    width: 100%;
  }

  /* Article Styles */
  article {
    padding: 4rem 0;
  }

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

  article h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 60px;
    height: 4px;
    background: linear-gradient(to right, var(--primary), var(--secondary));
    border-radius: 2px;
  }

  article h3 {
    font-size: 1.5rem;
    color: var(--secondary);
    margin: 2.5rem 0 1.5rem;
  }

  article p {
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
    line-height: 1.8;
  }

  /* Code Blocks */
  pre {
    background: #2d2d2d;
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin: 2rem 0;
    overflow: auto;
    box-shadow: var(--shadow);
  }

  code {
    font-family: 'Fira Code', monospace;
    font-size: 0.9rem;
    color: #f8f8f2;
  }

  .language-css {
    display: block;
    white-space: pre;
  }

  /* Card Styles */
  .card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin: 3rem 0;
  }

  .card {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    padding: 2rem;
    transition: var(--transition);
  }

  .card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.15);
  }

  .card-img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    border-radius: var(--border-radius);
    margin-bottom: 1.5rem;
    box-shadow: 0 4px 10px rgba(0,0,0,0.1);
  }

  /* Gallery */
  .image-gallery {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1.5rem;
    margin: 3rem 0;
  }

  .gallery-item {
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
  }

  .gallery-item:hover {
    transform: scale(1.03);
  }

  .gallery-img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    display: block;
  }

  /* Footer */
  footer {
    background: linear-gradient(135deg, #2c3e50, #34495e);
    color: white;
    padding: 4rem 0 2rem;
  }

  .footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
  }

  .footer-section h4 {
    font-size: 1.2rem;
    margin-bottom: 1.5rem;
    position: relative;
    padding-bottom: 0.5rem;
  }

  .footer-section h4::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 40px;
    height: 2px;
    background: var(--primary);
  }

  .footer-section ul {
    list-style: none;
  }

  .footer-section li {
    margin-bottom: 0.8rem;
  }

  .footer-section a {
    color: rgba(255,255,255,0.7);
    text-decoration: none;
    transition: var(--transition);
  }

  .footer-section a:hover {
    color: white;
    padding-left: 5px;
  }

  .copyright {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255,255,255,0.1);
    color: rgba(255,255,255,0.6);
    font-size: 0.9rem;
  }

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

  .fade-in {
    animation: fadeIn 0.8s ease-out forwards;
  }

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

  /* Responsive */
  @media (max-width: 768px) {
    .nav-container {
      flex-direction: column;
      padding: 1rem;
    }

    .nav-menu {
      margin-top: 1rem;
    }

    .nav-item {
      margin-left: 1rem;
    }

    .header-title {
      font-size: 2rem;
    }

    article {
      padding: 2rem 0;
    }

    article h2 {
      font-size: 1.8rem;
    }

    article h3 {
      font-size: 1.3rem;
    }
  }

  @media (max-width: 480px) {
    .nav-menu {
      flex-direction: column;
      align-items: center;
    }

    .nav-item {
      margin: 0.5rem 0;
    }

    .header-content {
      padding: 1rem;
    }

    .header-title {
      font-size: 1.8rem;
    }
  }