:root {
    --primary-color: #1e3c72;
    --secondary-color: #2a5298;
    --accent-color: #00aaff;
    --text-color: #333;
    --light-bg: rgba(255, 255, 255, 0.9);
    --dark-bg: rgba(30, 60, 114, 0.9);
    --card-bg: rgba(255, 255, 255, 0.1);
    --transition: all 0.3s ease;
  }

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

  body {
    font-family: 'Roboto', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background: linear-gradient(135deg, #f5f7fa 0%, #e4e8f0 100%);
    overflow-x: hidden;
  }

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

  .header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 80px 0;
    text-align: center;
    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: 0.1;
    z-index: 0;
  }

  .header-content {
    position: relative;
    z-index: 1;
  }

  h1 {
    font-size: 3rem;
    margin-bottom: 20px;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
  }

  .subtitle {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto 30px;
    opacity: 0.9;
  }

  .notice {
    background: rgba(255, 255, 255, 0.2);
    padding: 15px;
    border-radius: 8px;
    display: inline-block;
    margin-top: 30px;
    backdrop-filter: blur(5px);
  }

  .navbar {
    position: sticky;
    top: 0;
    background: var(--dark-bg);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    z-index: 1000;
    padding: 15px 0;
  }

  .nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
  }

  .nav-logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: white;
    text-decoration: none;
  }

  .nav-menu {
    display: flex;
    list-style: none;
  }

  .nav-item {
    margin-left: 30px;
  }

  .nav-link {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    position: relative;
  }

  .nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent-color);
    transition: var(--transition);
  }

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

  .article-container {
    background: white;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
    margin: 50px auto;
    padding: 50px;
    position: relative;
    overflow: hidden;
  }

  .article-container::before {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 300px;
    height: 300px;
    background: url('https://images.gptkong.com/demo/sample2.png') center/cover no-repeat;
    opacity: 0.1;
    z-index: 0;
  }

  article {
    position: relative;
    z-index: 1;
  }

  h2 {
    font-size: 2rem;
    color: var(--primary-color);
    margin: 40px 0 20px;
    position: relative;
    padding-bottom: 10px;
  }

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

  h3 {
    font-size: 1.5rem;
    color: var(--secondary-color);
    margin: 30px 0 15px;
  }

  p {
    margin-bottom: 20px;
    font-size: 1.1rem;
    line-height: 1.8;
  }

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

  .image-card {
    border-radius: 10px;
    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 10px 25px rgba(0, 0, 0, 0.15);
  }

  .image-card img {
    width: 100%;
    height: auto;
    display: block;
    border-radius: 10px;
  }

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

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

  .language-css {
    color: #d63384;
  }

  .card {
    background: var(--light-bg);
    border-radius: 10px;
    padding: 30px;
    margin: 30px 0;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    transition: var(--transition);
  }

  .card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
  }

  .footer {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 50px 0;
    text-align: center;
  }

  .footer p {
    opacity: 0.8;
    margin-bottom: 0;
  }

  @media (max-width: 768px) {
    .nav-menu {
      display: none;
    }

    h1 {
      font-size: 2rem;
    }

    .article-container {
      padding: 30px;
    }

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

  /* Animations */
  @keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
  }

  .floating {
    animation: float 3s ease-in-out infinite;
  }

  /* Scroll indicator */
  .scroll-progress {
    position: fixed;
    top: 0;
    left: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
    z-index: 1001;
    transition: width 0.1s;
  }