:root {
    --primary: #1E3C72;
    --secondary: #2A5298;
    --accent: #FF7E5F;
    --light: #F5F7FA;
    --dark: #0F172A;
    --text: #334155;
    --gradient: linear-gradient(135deg, var(--primary), var(--secondary));
  }

  * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Roboto', system-ui, -apple-system, sans-serif;
  }

  body {
    background-color: var(--light);
    color: var(--text);
    line-height: 1.6;
    overflow-x: hidden;
  }

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

  header {
    background: var(--gradient);
    color: white;
    padding: 2rem 0;
    position: relative;
    overflow: hidden;
    margin-bottom: 3rem;
    box-shadow: 0 4px 30px 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;
    text-align: center;
  }

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

  .header-content p {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto 2rem;
  }

  .notice {
    background: rgba(255, 255, 255, 0.2);
    padding: 1rem;
    border-radius: 8px;
    display: inline-block;
    margin-top: 1rem;
    backdrop-filter: blur(5px);
  }

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

  article {
    background: white;
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
  }

  article h2 {
    color: var(--primary);
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
    position: relative;
    padding-bottom: 0.5rem;
  }

  article h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 60px;
    height: 3px;
    background: var(--accent);
    border-radius: 3px;
  }

  article h3 {
    color: var(--secondary);
    font-size: 1.4rem;
    margin: 1.8rem 0 1rem;
  }

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

  pre {
    background: #f8fafc;
    border-radius: 8px;
    padding: 1.2rem;
    margin: 1.5rem 0;
    overflow: auto;
    border-left: 4px solid var(--accent);
    font-family: 'Fira Code', monospace;
    font-size: 0.9rem;
    line-height: 1.5;
  }

  code {
    background: #f1f5f9;
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    font-family: 'Fira Code', monospace;
    font-size: 0.9rem;
  }

  table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5rem 0;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
  }

  th, td {
    padding: 0.8rem;
    text-align: left;
    border-bottom: 1px solid #e2e8f0;
  }

  th {
    background: var(--primary);
    color: white;
  }

  tr:nth-child(even) {
    background: #f8fafc;
  }

  .sidebar {
    position: sticky;
    top: 2rem;
    align-self: start;
  }

  .nav-card {
    background: white;
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    margin-bottom: 2rem;
  }

  .nav-card h3 {
    color: var(--primary);
    margin-bottom: 1rem;
    font-size: 1.2rem;
  }

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

  .nav-links li {
    margin-bottom: 0.6rem;
  }

  .nav-links a {
    color: var(--text);
    text-decoration: none;
    display: block;
    padding: 0.5rem 0;
    transition: all 0.3s ease;
    position: relative;
  }

  .nav-links a::before {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent);
    transition: width 0.3s ease;
  }

  .nav-links a:hover {
    color: var(--accent);
    padding-left: 0.5rem;
  }

  .nav-links a:hover::before {
    width: 20px;
  }

  .gallery {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
    margin-top: 1.5rem;
  }

  .gallery img {
    width: 100%;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
  }

  .gallery img:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 15px rgba(0, 0, 0, 0.1);
  }

  footer {
    background: var(--gradient);
    color: white;
    padding: 2rem 0;
    text-align: center;
    margin-top: 3rem;
  }

  .footer-content {
    max-width: 800px;
    margin: 0 auto;
  }

  @media (max-width: 768px) {
    .article-container {
      grid-template-columns: 1fr;
    }
    
    .sidebar {
      position: static;
      order: -1;
      margin-bottom: 2rem;
    }
    
    header h1 {
      font-size: 2rem;
    }
  }

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

  article {
    animation: fadeIn 0.6s ease-out forwards;
  }

  /* Code block styling */
  pre code {
    background: none;
    padding: 0;
    border-radius: 0;
  }

  /* Custom scrollbar */
  ::-webkit-scrollbar {
    width: 8px;
  }

  ::-webkit-scrollbar-track {
    background: #f1f1f1;
  }

  ::-webkit-scrollbar-thumb {
    background: var(--primary);
    border-radius: 4px;
  }

  ::-webkit-scrollbar-thumb:hover {
    background: var(--secondary);
  }