:root {
    --primary: #3498db;
    --secondary: #9b59b6;
    --accent: #e67e22;
    --success: #2ecc71;
    --text: #2c3e50;
    --light: #ecf0f1;
    --dark: #34495e;
    --radius: 12px;
    --shadow: 0 10px 30px 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: 'Open Sans', 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text);
    background: linear-gradient(135deg, #f5f7fa 0%, #e4e8eb 100%);
    min-height: 100%;
    padding: 0;
    margin: 0;
  }

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

  header {
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
    padding: 2rem 0;
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow);
  }

  header::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--accent), var(--success));
    animation: rainbow 8s linear infinite;
  }

  @keyframes rainbow {
    0% { background-position: 0% 50%; }
    100% { background-position: 100% 50%; }
  }

  .header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: relative;
    z-index: 2;
  }

  .logo {
    font-size: 1.8rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 10px;
  }

  .logo::before {
    content: "";
    display: block;
    width: 40px;
    height: 40px;
    background: url('https://images.gptkong.com/demo/sample1.png') center/cover;
    border-radius: 50%;
    border: 2px solid white;
  }

  .notice {
    background: rgba(255,255,255,0.2);
    padding: 10px 20px;
    border-radius: 30px;
    font-size: 0.9rem;
    backdrop-filter: blur(5px);
  }

  nav ul {
    display: flex;
    list-style: none;
    gap: 20px;
  }

  nav a {
    color: white;
    text-decoration: none;
    font-weight: 600;
    padding: 8px 16px;
    border-radius: 30px;
    transition: var(--transition);
  }

  nav a:hover {
    background: rgba(255,255,255,0.2);
  }

  .hero {
    padding: 4rem 0;
    text-align: center;
    position: relative;
  }

  .hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: fadeIn 1s ease-out;
  }

  @keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
  }

  .hero p {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto 2rem;
    color: var(--dark);
  }

  .card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin: 3rem 0;
  }

  .card {
    background: white;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    overflow: hidden;
    transition: var(--transition);
    position: relative;
  }

  .card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 35px rgba(0,0,0,0.15);
  }

  .card-image {
    height: 200px;
    background-size: cover;
    background-position: center;
    position: relative;
  }

  .card-image::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 100%;
    background: linear-gradient(to top, rgba(0,0,0,0.7), transparent);
  }

  .card-content {
    padding: 1.5rem;
  }

  .card h3 {
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
    color: var(--dark);
  }

  .card .subtitle {
    color: var(--secondary);
    font-weight: 600;
    margin-bottom: 1rem;
    display: block;
  }

  .card p {
    color: var(--text);
    margin-bottom: 1.5rem;
  }

  .card-badge {
    position: absolute;
    top: 15px;
    right: 15px;
    background: white;
    color: var(--dark);
    padding: 5px 10px;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
    box-shadow: 0 3px 10px rgba(0,0,0,0.1);
  }

  .article-container {
    background: white;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 3rem;
    margin: 3rem 0;
  }

  article h2 {
    font-size: 2rem;
    color: var(--primary);
    margin-bottom: 1.5rem;
    position: relative;
    padding-bottom: 10px;
  }

  article h2::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
  }

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

  article h4 {
    font-size: 1.2rem;
    color: var(--dark);
    margin: 1.5rem 0 1rem;
  }

  article p {
    margin-bottom: 1.2rem;
    line-height: 1.7;
  }

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

  pre {
    background: #f8f9fa;
    border-radius: 8px;
    padding: 1.5rem;
    margin: 1.5rem 0;
    overflow-x: auto;
    font-family: 'Courier New', monospace;
    border-left: 4px solid var(--primary);
    box-shadow: inset 0 1px 3px rgba(0,0,0,0.1);
  }

  code {
    font-family: 'Courier New', monospace;
    color: var(--dark);
  }

  table {
    width: 100%;
    border-collapse: collapse;
    margin: 2rem 0;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
  }

  th, td {
    padding: 12px 15px;
    text-align: left;
    border-bottom: 1px solid #ddd;
  }

  th {
    background: var(--primary);
    color: white;
    font-weight: 600;
  }

  tr:nth-child(even) {
    background: #f8f9fa;
  }

  tr:hover {
    background: #f1f3f5;
  }

  .image-gallery {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 20px;
    margin: 2rem 0;
  }

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

  .gallery-image:hover {
    transform: scale(1.03);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
  }

  .gallery-image img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    display: block;
  }

  footer {
    background: var(--dark);
    color: white;
    padding: 3rem 0;
    margin-top: 3rem;
  }

  .footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
  }

  .footer-section h3 {
    font-size: 1.2rem;
    margin-bottom: 1rem;
    color: var(--light);
    position: relative;
    padding-bottom: 10px;
  }

  .footer-section h3::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 40px;
    height: 2px;
    background: var(--primary);
  }

  .footer-section ul {
    list-style: none;
  }

  .footer-section li {
    margin-bottom: 0.8rem;
  }

  .footer-section a {
    color: #bdc3c7;
    text-decoration: none;
    transition: color 0.3s;
  }

  .footer-section a:hover {
    color: white;
  }

  .copyright {
    text-align: center;
    padding-top: 2rem;
    margin-top: 2rem;
    border-top: 1px solid rgba(255,255,255,0.1);
    color: #bdc3c7;
    font-size: 0.9rem;
  }

  @media (max-width: 768px) {
    .header-content {
      flex-direction: column;
      text-align: center;
      gap: 1rem;
    }

    nav ul {
      flex-wrap: wrap;
      justify-content: center;
    }

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

    .article-container {
      padding: 2rem;
    }
  }

  @media (max-width: 480px) {
    .card-grid {
      grid-template-columns: 1fr;
    }

    .article-container {
      padding: 1.5rem;
    }
  }