:root {
    --primary-color: #0D47A1;
    --secondary-color: #607D8B;
    --accent-color: #FF9800;
    --background-color: #F5F5F5;
    --text-color: #333333;
    --light-text: #FFFFFF;
    --card-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    --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', 'Open Sans', sans-serif;
    background: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
    overflow-x: hidden;
  }

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

  header {
    background: linear-gradient(135deg, var(--primary-color) 0%, #1565C0 100%);
    color: var(--light-text);
    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;
    background-size: cover;
    opacity: 0.1;
    z-index: 0;
  }

  .header-content {
    position: relative;
    z-index: 1;
    text-align: center;
    padding: 2rem;
  }

  h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    font-weight: 700;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
  }

  .tagline {
    font-size: 1.2rem;
    opacity: 0.9;
    margin-bottom: 2rem;
  }

  .notice {
    background: rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
    padding: 1rem;
    border-radius: 8px;
    display: inline-block;
    margin-top: 1rem;
    border: 1px solid rgba(255, 255, 255, 0.3);
  }

  .nav-container {
    background: rgba(13, 71, 161, 0.9);
    backdrop-filter: blur(10px);
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  }

  nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    max-width: 1200px;
    margin: 0 auto;
  }

  .nav-links {
    display: flex;
    gap: 2rem;
  }

  .nav-links a {
    color: var(--light-text);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    position: relative;
    padding: 0.5rem 0;
  }

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

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

  .main-content {
    padding: 3rem 0;
  }

  article {
    background: white;
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--card-shadow);
    margin-bottom: 3rem;
  }

  h2 {
    color: var(--primary-color);
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--secondary-color);
  }

  h3 {
    color: var(--primary-color);
    font-size: 1.5rem;
    margin: 2rem 0 1rem;
  }

  p {
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
  }

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

  .image-card {
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: var(--transition);
  }

  .image-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.15);
  }

  .image-card img {
    width: 100%;
    height: auto;
    display: block;
    border-radius: 8px;
  }

  pre {
    background: #263238;
    color: #ECEFF1;
    padding: 1.5rem;
    border-radius: 8px;
    overflow-x: auto;
    margin: 2rem 0;
    font-family: 'Courier New', monospace;
    font-size: 0.95rem;
    line-height: 1.5;
    position: relative;
  }

  pre::before {
    content: 'CSS';
    position: absolute;
    top: 0;
    left: 0;
    background: var(--accent-color);
    color: white;
    padding: 0.2rem 0.8rem;
    font-size: 0.8rem;
    border-radius: 0 0 4px 0;
  }

  code {
    font-family: 'Courier New', monospace;
    background: rgba(255, 152, 0, 0.1);
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    font-size: 0.9rem;
  }

  table {
    width: 100%;
    border-collapse: collapse;
    margin: 2rem 0;
    box-shadow: 0 2px 3px rgba(0, 0, 0, 0.1);
  }

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

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

  tr:nth-child(even) {
    background: #f9f9f9;
  }

  tr:hover {
    background: #f1f1f1;
  }

  .highlight {
    color: var(--accent-color);
    font-weight: 600;
  }

  footer {
    background: linear-gradient(135deg, var(--primary-color) 0%, #0D47A1 100%);
    color: var(--light-text);
    padding: 3rem 0;
    text-align: center;
  }

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

  .footer-links {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin: 1.5rem 0;
  }

  .footer-links a {
    color: var(--light-text);
    text-decoration: none;
    transition: var(--transition);
  }

  .footer-links a:hover {
    color: var(--accent-color);
  }

  @media (max-width: 768px) {
    .nav-links {
      gap: 1rem;
    }

    h1 {
      font-size: 2rem;
    }

    .header-content {
      padding: 1rem;
    }

    article {
      padding: 1.5rem;
    }
  }

  @media (max-width: 480px) {
    nav {
      flex-direction: column;
      gap: 1rem;
      padding: 1rem;
    }

    .nav-links {
      flex-wrap: wrap;
      justify-content: center;
    }

    h2 {
      font-size: 1.5rem;
    }

    h3 {
      font-size: 1.3rem;
    }
  }