:root {
    --primary-color: #1E90FF;
    --secondary-color: #FFD700;
    --background-color: #FFFFFF;
    --text-color: #333333;
    --light-blue: #87CEFA;
    --dark-blue: #0066CC;
    --gray: #F5F5F5;
    --dark-gray: #555555;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
  }

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

  body {
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
    font-size: 16px;
    overflow-x: hidden;
  }

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

  /* Header Styles */
  .header {
    background: linear-gradient(135deg, var(--primary-color), var(--light-blue));
    color: white;
    padding: 80px 0;
    text-align: center;
    position: relative;
    overflow: hidden;
    margin-bottom: 60px;
  }

  .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;
    background-size: contain;
  }

  .header h1 {
    font-size: 2.8rem;
    margin-bottom: 20px;
    position: relative;
    z-index: 1;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
  }

  .header p {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
  }

  /* Navigation */
  .navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background-color: var(--primary-color);
    padding: 15px 0;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    z-index: 1000;
  }

  .nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
  }

  .logo {
    color: white;
    font-size: 1.5rem;
    font-weight: bold;
    text-decoration: none;
  }

  .nav-links {
    display: flex;
    gap: 30px;
  }

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

  .nav-links a:hover {
    color: var(--secondary-color);
  }

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

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

  /* Main Content */
  .main-content {
    padding: 100px 0 60px;
  }

  article {
    background-color: white;
    border-radius: 12px;
    box-shadow: var(--shadow);
    padding: 40px;
    margin-bottom: 60px;
  }

  article h2 {
    color: var(--primary-color);
    font-size: 2rem;
    margin-bottom: 30px;
    position: relative;
    padding-bottom: 15px;
  }

  article h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 60px;
    height: 3px;
    background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
  }

  article h3 {
    color: var(--primary-color);
    font-size: 1.5rem;
    margin: 30px 0 20px;
  }

  article p {
    margin-bottom: 20px;
    font-size: 1.1rem;
  }

  .highlight {
    color: var(--secondary-color);
    font-weight: bold;
  }

  /* Code Blocks */
  pre {
    background-color: #f8f8f8;
    border-radius: 8px;
    padding: 20px;
    margin: 20px 0;
    overflow: auto;
    border-left: 4px solid var(--primary-color);
  }

  code {
    font-family: 'Courier New', monospace;
    color: #333;
  }

  /* Grid Layout */
  .grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin: 40px 0;
  }

  .card {
    background-color: white;
    border-radius: 12px;
    box-shadow: var(--shadow);
    padding: 25px;
    transition: var(--transition);
  }

  .card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.15);
  }

  .card img {
    width: 100%;
    border-radius: 8px;
    margin-bottom: 20px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
    transition: var(--transition);
  }

  .card:hover img {
    transform: scale(1.02);
  }

  .card h4 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 1.3rem;
  }

  /* Buttons */
  .button {
    display: inline-block;
    background: linear-gradient(to right, var(--primary-color), var(--light-blue));
    color: white;
    padding: 12px 25px;
    border-radius: 30px;
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    border: none;
    cursor: pointer;
    box-shadow: 0 4px 15px rgba(30, 144, 255, 0.3);
    margin: 10px 0;
  }

  .button:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(30, 144, 255, 0.4);
  }

  /* Footer */
  .footer {
    background: linear-gradient(135deg, var(--primary-color), var(--dark-blue));
    color: white;
    padding: 50px 0;
    text-align: center;
  }

  .footer p {
    margin-bottom: 20px;
  }

  .footer-links {
    display: flex;
    justify-content: center;
    gap: 30px;
    margin-bottom: 30px;
  }

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

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

  /* Responsive Design */
  @media (max-width: 768px) {
    .header h1 {
      font-size: 2rem;
    }

    .nav-links {
      gap: 15px;
    }

    article {
      padding: 30px;
    }

    .grid-container {
      grid-template-columns: 1fr;
    }
  }

  @media (max-width: 480px) {
    .header {
      padding: 60px 0;
    }

    .header h1 {
      font-size: 1.8rem;
    }

    .nav-container {
      flex-direction: column;
      gap: 15px;
    }

    article {
      padding: 20px;
    }
  }

  /* Animation */
  @keyframes float {
    0%, 100% {
      transform: translateY(0);
    }
    50% {
      transform: translateY(-10px);
    }
  }

  .floating {
    animation: float 3s ease-in-out infinite;
  }

  /* Reference Note */
  .reference-note {
    background-color: var(--gray);
    padding: 15px;
    border-radius: 8px;
    margin: 30px 0;
    text-align: center;
    font-style: italic;
    color: var(--dark-gray);
  }