:root {
    --primary-color: #003366;
    --secondary-color: #00cc66;
    --background-color: #f5f5f5;
    --accent-color: #ff6600;
    --font-color: #333333;
    --card-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.1);
  }

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

  body {
    font-family: 'Roboto', sans-serif;
    color: var(--font-color);
    background: linear-gradient(135deg, #f9f9f9 0%, #eef2f5 100%);
    line-height: 1.6;
    overflow-x: hidden;
  }

  .design-notice {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: rgba(0, 51, 102, 0.9);
    color: white;
    padding: 12px 20px;
    border-radius: 30px;
    font-size: 14px;
    z-index: 1000;
    box-shadow: var(--card-shadow);
    backdrop-filter: blur(5px);
  }

  .hero {
    height: 80vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    background: linear-gradient(45deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    text-align: center;
    padding: 0 20px;
  }

  .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: 0.1;
  }

  .hero-content {
    max-width: 800px;
    position: relative;
    z-index: 2;
  }

  .hero h1 {
    font-size: 3.5rem;
    margin-bottom: 1.5rem;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
  }

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

  .scroll-indicator {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    animation: bounce 2s infinite;
  }

  @keyframes bounce {
    0%, 20%, 50%, 80%, 100% {transform: translateY(0);}
    40% {transform: translateY(-20px);}
    60% {transform: translateY(-10px);}
  }

  .container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 20px;
  }

  article {
    background: white;
    border-radius: 12px;
    box-shadow: var(--card-shadow);
    padding: 50px;
    margin: 40px 0;
    position: relative;
    overflow: hidden;
  }

  article::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 5px;
    height: 100%;
    background: linear-gradient(to bottom, var(--primary-color), var(--secondary-color));
  }

  h2 {
    font-size: 2.2rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    position: relative;
    padding-bottom: 15px;
  }

  h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 60px;
    height: 4px;
    background: var(--accent-color);
    border-radius: 2px;
  }

  h3 {
    font-size: 1.8rem;
    color: var(--secondary-color);
    margin: 2rem 0 1rem;
  }

  h4 {
    font-size: 1.4rem;
    color: var(--primary-color);
    margin: 1.5rem 0 1rem;
  }

  p {
    font-size: 1.1rem;
    margin-bottom: 1.5rem;
    line-height: 1.8;
  }

  pre {
    background: #f8f9fa;
    border-radius: 8px;
    padding: 20px;
    margin: 1.5rem 0;
    overflow-x: auto;
    position: relative;
    border-left: 4px solid var(--accent-color);
  }

  code {
    font-family: 'Courier New', monospace;
    font-size: 0.95rem;
    color: #333;
  }

  .image-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
    margin: 2rem 0;
  }

  .image-card {
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--card-shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
  }

  .image-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px -10px rgba(0, 0, 0, 0.2);
  }

  .image-card img {
    width: 100%;
    height: auto;
    display: block;
    transition: transform 0.5s ease;
  }

  .image-card:hover img {
    transform: scale(1.05);
  }

  .tab-demo {
    background: white;
    border-radius: 12px;
    box-shadow: var(--card-shadow);
    padding: 30px;
    margin: 3rem 0;
  }

  .tab-header {
    display: flex;
    border-bottom: 1px solid #eee;
    margin-bottom: 20px;
  }

  .tab-btn {
    padding: 12px 24px;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    color: #666;
    position: relative;
    transition: all 0.3s ease;
  }

  .tab-btn.active {
    color: var(--primary-color);
    font-weight: bold;
  }

  .tab-btn.active::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 0;
    width: 100%;
    height: 3px;
    background: var(--accent-color);
  }

  .tab-content {
    display: none;
    animation: fadeIn 0.5s ease;
  }

  .tab-content.active {
    display: block;
  }

  @keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
  }

  .card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
    margin: 2rem 0;
  }

  .card {
    background: white;
    border-radius: 12px;
    padding: 25px;
    box-shadow: var(--card-shadow);
    transition: all 0.3s ease;
    border: 1px solid #eee;
  }

  .card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px -10px rgba(0, 0, 0, 0.15);
  }

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

  .card p {
    font-size: 1rem;
  }

  .footer {
    background: var(--primary-color);
    color: white;
    padding: 40px 0;
    text-align: center;
    margin-top: 60px;
  }

  .footer p {
    opacity: 0.8;
    font-size: 0.9rem;
  }

  @media (max-width: 768px) {
    .hero h1 {
      font-size: 2.5rem;
    }
    
    article {
      padding: 30px 20px;
    }
    
    .container {
      padding: 20px 15px;
    }
    
    .image-grid {
      grid-template-columns: 1fr;
    }
  }