:root {
    --primary: #1E3C72;
    --primary-light: #2A5298;
    --secondary: #4A4A4A;
    --accent: #FF8C00;
    --accent-light: #FFA500;
    --text: #333333;
    --text-light: #666666;
    --bg: #F8F9FA;
    --card-bg: #FFFFFF;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
  }

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

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

  .header {
    background: linear-gradient(135deg, var(--primary), var(--primary-light));
    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/sample3.png') center/cover no-repeat;
    opacity: 0.15;
    z-index: 0;
  }

  .header-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    position: relative;
    z-index: 1;
  }

  .title {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    font-weight: 700;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
  }

  .subtitle {
    font-size: 1.25rem;
    opacity: 0.9;
    max-width: 800px;
    margin-bottom: 2rem;
  }

  .notice {
    background: rgba(255, 255, 255, 0.2);
    padding: 1rem;
    border-radius: 8px;
    display: inline-block;
    margin-bottom: 2rem;
    backdrop-filter: blur(5px);
  }

  .grid-container {
    max-width: 1200px;
    margin: 3rem auto;
    padding: 0 2rem;
  }

  .article-grid {
    display: grid;
    grid-template-columns: 250px 1fr;
    gap: 2rem;
  }

  .nav-sidebar {
    position: sticky;
    top: 2rem;
    align-self: start;
    background: var(--card-bg);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: var(--shadow);
  }

  .nav-title {
    font-size: 1.1rem;
    margin-bottom: 1rem;
    color: var(--primary);
    font-weight: 600;
  }

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

  .nav-links li {
    margin-bottom: 0.75rem;
  }

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

  .nav-links a:hover::before {
    width: 100%;
  }

  .article-content {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 2.5rem;
    box-shadow: var(--shadow);
  }

  article h2 {
    font-size: 1.8rem;
    color: var(--primary);
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid rgba(30, 60, 114, 0.1);
  }

  article h3 {
    font-size: 1.4rem;
    color: var(--primary-light);
    margin: 2rem 0 1rem;
  }

  article p {
    margin-bottom: 1.5rem;
    font-size: 1.05rem;
    line-height: 1.7;
  }

  pre {
    background: #1E3C72;
    border-radius: 8px;
    padding: 1.5rem;
    margin: 1.5rem 0;
    overflow: auto;
    position: relative;
  }

  code {
    font-family: 'Courier New', monospace;
    color: #E6E6E6;
    font-size: 0.95rem;
    line-height: 1.5;
  }

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

  .image-card {
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    height: 300px;
  }

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

  .image-card img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s ease;
  }

  .image-card:hover img {
    transform: scale(1.05);
  }

  .summary-card {
    background: linear-gradient(135deg, var(--primary), var(--primary-light));
    color: white;
    padding: 2rem;
    border-radius: 12px;
    margin: 3rem 0;
    position: relative;
    overflow: hidden;
  }

  .summary-card::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: url('https://images.gptkong.com/demo/sample6.png') center/cover no-repeat;
    opacity: 0.1;
    z-index: 0;
    animation: rotate 60s linear infinite;
  }

  @keyframes rotate {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
  }

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

  .summary-card h3 {
    color: white;
    font-size: 1.5rem;
    margin-bottom: 1rem;
  }

  .summary-card p {
    opacity: 0.9;
  }

  @media (max-width: 900px) {
    .article-grid {
      grid-template-columns: 1fr;
    }

    .nav-sidebar {
      position: static;
      margin-bottom: 2rem;
    }
  }

  @media (max-width: 600px) {
    .header-content {
      padding: 0 1.5rem;
    }

    .title {
      font-size: 2rem;
    }

    .subtitle {
      font-size: 1.1rem;
    }

    .article-content {
      padding: 1.5rem;
    }

    article h2 {
      font-size: 1.5rem;
    }

    article h3 {
      font-size: 1.25rem;
    }
  }