:root {
    --primary: #0066ff;
    --secondary: #9c27b0;
    --accent: #ffeb3b;
    --dark: #212121;
    --light: #f5f5f5;
    --gradient: linear-gradient(135deg, var(--primary), var(--secondary));
  }
  
  * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  
  @font-face {
    font-family: 'Roboto';
    src: url('https://fonts.googleapis.com/css2?family=Roboto:wght@300;400;500;700&display=swap');
  }
  
  body {
    font-family: 'Roboto', sans-serif;
    color: var(--dark);
    line-height: 1.7;
    background: var(--light);
    overflow-x: hidden;
  }
  
  .notice {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: rgba(0,0,0,0.8);
    color: white;
    text-align: center;
    padding: 10px;
    z-index: 9999;
    font-size: 14px;
  }
  
  .hero {
    min-height: 500px;
    background: var(--gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    text-align: center;
    padding: 80px 20px;
    position: relative;
    overflow: hidden;
    margin-top: 40px;
  }
  
  .hero::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: 0.2;
    z-index: 0;
  }
  
  .hero-content {
    position: relative;
    z-index: 1;
    max-width: 800px;
  }
  
  h1 {
    font-size: 3.5rem;
    margin-bottom: 20px;
    text-shadow: 0 2px 10px rgba(0,0,0,0.3);
    animation: fadeIn 1s ease;
  }
  
  .hero p {
    font-size: 1.2rem;
    margin-bottom: 30px;
    animation: fadeIn 1s ease 0.3s forwards;
    opacity: 0;
  }
  
  @keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
  }
  
  .navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: rgba(255,255,255,0.95);
    box-shadow: 0 2px 15px rgba(0,0,0,0.1);
    z-index: 1000;
    padding: 15px 0;
    backdrop-filter: blur(10px);
  }
  
  .nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
  }
  
  .logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
    text-decoration: none;
  }
  
  .nav-links {
    display: flex;
    list-style: none;
  }
  
  .nav-links li {
    margin-left: 30px;
  }
  
  .nav-links a {
    color: var(--dark);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
  }
  
  .nav-links a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary);
    transition: width 0.3s ease;
  }
  
  .nav-links a:hover {
    color: var(--primary);
  }
  
  .nav-links a:hover::after {
    width: 100%;
  }
  
  .container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 20px;
  }
  
  article {
    background: white;
    border-radius: 15px;
    box-shadow: 0 5px 25px rgba(0,0,0,0.05);
    padding: 50px;
    margin-bottom: 60px;
  }
  
  article h2 {
    font-size: 2.5rem;
    color: var(--primary);
    margin-bottom: 30px;
    position: relative;
    padding-bottom: 15px;
  }
  
  article h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 80px;
    height: 4px;
    background: var(--gradient);
    border-radius: 2px;
  }
  
  article h3 {
    font-size: 1.8rem;
    color: var(--secondary);
    margin: 40px 0 20px;
  }
  
  article p {
    font-size: 1.1rem;
    margin-bottom: 25px;
    color: #444;
  }
  
  pre {
    background: #f8f8f8;
    border-radius: 8px;
    padding: 20px;
    margin: 30px 0;
    overflow-x: auto;
    box-shadow: inset 0 0 10px rgba(0,0,0,0.05);
    border-left: 4px solid var(--primary);
  }
  
  code {
    font-family: 'Courier New', monospace;
    color: #333;
  }
  
  .image-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 30px;
    margin: 40px 0;
  }
  
  .image-card {
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 10px 20px rgba(0,0,0,0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
  }
  
  .image-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0,0,0,0.15);
  }
  
  .image-card img {
    width: 100%;
    height: auto;
    display: block;
    transition: transform 0.5s ease;
  }
  
  .image-card:hover img {
    transform: scale(1.05);
  }
  
  .features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin: 50px 0;
  }
  
  .feature-card {
    background: white;
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.05);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    text-align: center;
  }
  
  .feature-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0,0,0,0.1);
  }
  
  .feature-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 20px;
    background: var(--gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 2rem;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
  }
  
  .feature-card h4 {
    font-size: 1.3rem;
    margin-bottom: 15px;
    color: var(--primary);
  }
  
  footer {
    background: var(--dark);
    color: white;
    padding: 60px 0 30px;
    text-align: center;
  }
  
  .footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
  }
  
  .footer-links {
    display: flex;
    justify-content: center;
    list-style: none;
    margin: 30px 0;
  }
  
  .footer-links li {
    margin: 0 15px;
  }
  
  .footer-links a {
    color: white;
    text-decoration: none;
    transition: color 0.3s ease;
  }
  
  .footer-links a:hover {
    color: var(--accent);
  }
  
  .copyright {
    margin-top: 30px;
    font-size: 0.9rem;
    opacity: 0.7;
  }
  
  @media (max-width: 768px) {
    h1 {
      font-size: 2.5rem;
    }
    
    .nav-links {
      display: none;
    }
    
    article {
      padding: 30px 20px;
    }
    
    .image-grid {
      grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    }
  }
  
  @media (max-width: 480px) {
    h1 {
      font-size: 2rem;
    }
    
    article h2 {
      font-size: 1.8rem;
    }
    
    article h3 {
      font-size: 1.5rem;
    }
    
    .image-grid {
      grid-template-columns: 1fr;
    }
    
    .features {
      grid-template-columns: 1fr;
    }
  }