:root {
    --primary: #0074D9;
    --secondary: #BDC3C7;
    --accent: #FFA500;
    --dark: #2C3E50;
    --light: #f0f4f8;
    --font-main: 'Roboto', sans-serif;
    --font-code: 'Courier New', monospace;
    --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
  }

  @font-face {
    font-family: 'Roboto';
    src: url('https://fonts.googleapis.com/css2?family=Roboto:wght@300;400;500;700&display=swap');
  }

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

  body {
    font-family: var(--font-main);
    background: radial-gradient(circle at 10% 20%, rgba(0, 116, 217, 0.1) 0%, rgba(189, 195, 199, 0.05) 90%);
    color: var(--dark);
    line-height: 1.6;
    padding-top: 80px;
  }

  .notification {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    color: white;
    text-align: center;
    padding: 15px;
    font-weight: 500;
    z-index: 2000;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  }

  .navbar {
    position: fixed;
    top: 40px;
    left: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    padding: 15px 5%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 15px rgba(0, 0, 0, 0.1);
    z-index: 1000;
  }

  .nav-links {
    display: flex;
    gap: 25px;
  }

  .nav-links a {
    color: var(--dark);
    text-decoration: none;
    font-weight: 500;
    position: relative;
    padding: 5px 0;
    transition: var(--transition);
  }

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

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

  .hero {
    height: 500px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, rgba(0, 116, 217, 0.8) 0%, rgba(189, 195, 199, 0.6) 100%);
    margin-bottom: 60px;
    position: relative;
    overflow: hidden;
  }

  .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: -1;
  }

  .hero-content {
    text-align: center;
    max-width: 800px;
    padding: 0 20px;
  }

  .hero h1 {
    font-size: 3rem;
    color: white;
    margin-bottom: 20px;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
  }

  .hero p {
    font-size: 1.2rem;
    color: white;
    opacity: 0.9;
    margin-bottom: 30px;
  }

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

  article {
    background: white;
    border-radius: 12px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    padding: 40px;
    margin-bottom: 60px;
  }

  article h2 {
    color: var(--primary);
    font-size: 1.8rem;
    margin: 30px 0 20px;
    position: relative;
    padding-left: 15px;
  }

  article h2:before {
    content: '';
    position: absolute;
    left: 0;
    top: 5px;
    height: 80%;
    width: 4px;
    background: var(--accent);
    border-radius: 2px;
  }

  article p {
    font-size: 1.1rem;
    margin-bottom: 20px;
    color: #555;
  }

  article strong {
    color: var(--dark);
    font-weight: 500;
  }

  article em {
    font-style: italic;
    color: var(--primary);
  }

  pre {
    background: #f8f9fa;
    border-radius: 8px;
    padding: 20px;
    margin: 25px 0;
    overflow-x: auto;
    box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.05);
    border-left: 4px solid var(--accent);
  }

  code {
    font-family: var(--font-code);
    font-size: 0.9rem;
    color: #333;
  }

  .image-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
    margin: 30px 0;
  }

  .image-card {
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    transition: var(--transition);
  }

  .image-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
  }

  .image-card img {
    width: 100%;
    height: 300px;
    object-fit: cover;
    display: block;
  }

  .accordion {
    margin: 30px 0;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  }

  .accordion-item {
    border-bottom: 1px solid #eee;
  }

  .accordion-header {
    padding: 15px 20px;
    background: #f8f9fa;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 500;
    transition: var(--transition);
  }

  .accordion-header:hover {
    background: #e9ecef;
  }

  .accordion-content {
    padding: 0 20px;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
  }

  .accordion-item.active .accordion-content {
    padding: 20px;
    max-height: 1000px;
  }

  footer {
    background: var(--dark);
    color: white;
    padding: 50px 0;
    text-align: center;
  }

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

  .footer-links {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin: 20px 0;
  }

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

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

  @media (max-width: 768px) {
    .navbar {
      flex-direction: column;
      padding: 15px;
    }

    .nav-links {
      margin-top: 15px;
      flex-wrap: wrap;
      justify-content: center;
    }

    .hero h1 {
      font-size: 2.2rem;
    }

    article {
      padding: 25px;
    }

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

  @media (max-width: 480px) {
    .hero h1 {
      font-size: 1.8rem;
    }

    article h2 {
      font-size: 1.5rem;
    }
  }