:root {
    --primary-color: #0d47a1;
    --secondary-color: #3949ab;
    --accent-color: #7e57c2;
    --highlight-color: #b39ddb;
    --text-color: #ffffff;
    --card-bg: #1e3a8a;
    --dark-bg: #121212;
    --light-bg: #f5f5f5;
  }

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

  body {
    font-family: 'Roboto', 'Helvetica', sans-serif;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--text-color);
    line-height: 1.6;
    letter-spacing: 0.5px;
    padding: 0;
    margin: 0;
    overflow-x: hidden;
  }

  .container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
  }

  header {
    text-align: center;
    padding: 3rem 0;
    position: relative;
    overflow: hidden;
  }

  header::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;
  }

  h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    background: linear-gradient(90deg, var(--highlight-color), var(--accent-color));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    text-shadow: 0 2px 4px rgba(0,0,0,0.2);
  }

  .tagline {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    color: rgba(255,255,255,0.8);
  }

  .reference-note {
    background: rgba(255,255,255,0.1);
    padding: 1rem;
    border-radius: 8px;
    margin: 2rem auto;
    max-width: 800px;
    text-align: center;
    border: 1px solid rgba(255,255,255,0.2);
    backdrop-filter: blur(5px);
  }

  article {
    background: rgba(30, 58, 138, 0.7);
    border-radius: 20px;
    padding: 3rem;
    margin: 2rem 0;
    box-shadow: 0 10px 30px rgba(0,0,0,0.3);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,0.1);
  }

  h2 {
    font-size: 2rem;
    margin: 2rem 0 1.5rem;
    color: var(--highlight-color);
    position: relative;
    padding-bottom: 0.5rem;
  }

  h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100px;
    height: 3px;
    background: linear-gradient(90deg, var(--accent-color), transparent);
  }

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

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

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

  .image-card {
    background: rgba(255,255,255,0.1);
    border-radius: 15px;
    overflow: hidden;
    transition: transform 0.3s, box-shadow 0.3s;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
  }

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

  .image-card img {
    width: 100%;
    height: auto;
    display: block;
    border-radius: 15px 15px 0 0;
  }

  .image-caption {
    padding: 1rem;
    text-align: center;
    font-size: 0.9rem;
    color: rgba(255,255,255,0.7);
  }

  pre {
    background: rgba(0,0,0,0.3);
    border-radius: 10px;
    padding: 1.5rem;
    margin: 1.5rem 0;
    overflow-x: auto;
    border-left: 4px solid var(--accent-color);
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
    line-height: 1.5;
    position: relative;
  }

  pre::before {
    content: 'CSS';
    position: absolute;
    top: 0;
    right: 0;
    background: var(--accent-color);
    color: white;
    padding: 0.2rem 0.5rem;
    font-size: 0.8rem;
    border-radius: 0 0 0 5px;
  }

  code {
    font-family: 'Courier New', monospace;
    background: rgba(0,0,0,0.2);
    padding: 0.2rem 0.4rem;
    border-radius: 3px;
    font-size: 0.9rem;
  }

  .nav-tabs {
    display: flex;
    justify-content: center;
    margin: 2rem 0;
    flex-wrap: wrap;
    gap: 1rem;
  }

  .nav-tab {
    padding: 0.8rem 1.5rem;
    background: rgba(255,255,255,0.1);
    border-radius: 30px;
    cursor: pointer;
    transition: all 0.3s;
    font-weight: 500;
    border: 1px solid rgba(255,255,255,0.2);
  }

  .nav-tab:hover {
    background: var(--accent-color);
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
  }

  .section-divider {
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
    margin: 3rem 0;
  }

  .floating-element {
    position: absolute;
    width: 100px;
    height: 100px;
    background: rgba(179, 157, 219, 0.2);
    border-radius: 50%;
    filter: blur(30px);
    z-index: -1;
    animation: float 15s infinite ease-in-out;
  }

  @keyframes float {
    0%, 100% { transform: translate(0, 0); }
    25% { transform: translate(50px, 50px); }
    50% { transform: translate(0, 100px); }
    75% { transform: translate(-50px, 50px); }
  }

  footer {
    text-align: center;
    padding: 2rem;
    margin-top: 3rem;
    color: rgba(255,255,255,0.6);
    font-size: 0.9rem;
  }

  @media (max-width: 768px) {
    .container {
      padding: 1rem;
    }
    
    article {
      padding: 1.5rem;
    }
    
    h1 {
      font-size: 2rem;
    }
    
    h2 {
      font-size: 1.5rem;
    }
    
    h3 {
      font-size: 1.2rem;
    }
  }