:root {
    --primary: #1E273B;
    --secondary: #651FFF;
    --accent: #4B00C6;
    --light: #FFFFFF;
    --gray: #F5F5F5;
    --dark: #121212;
    --spacing: 20px;
    --border-radius: 8px;
    --transition: all 0.3s ease;
  }

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

  body {
    font-family: 'Roboto', 'Open Sans', sans-serif;
    line-height: 1.6;
    color: var(--dark);
    background: linear-gradient(135deg, var(--gray) 0%, var(--light) 100%);
    min-height: 100%;
    overflow-x: hidden;
  }

  .container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing);
  }

  header {
    background: linear-gradient(90deg, var(--primary) 0%, var(--secondary) 100%);
    color: var(--light);
    padding: var(--spacing) 0;
    position: relative;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  }

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

  .logo {
    font-size: 1.8rem;
    font-weight: 700;
    letter-spacing: 1px;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
  }

  .nav-links {
    display: flex;
    gap: var(--spacing);
  }

  .nav-links a {
    color: var(--light);
    text-decoration: none;
    font-weight: 500;
    padding: 8px 12px;
    border-radius: var(--border-radius);
    transition: var(--transition);
  }

  .nav-links a:hover {
    background-color: rgba(255, 255, 255, 0.1);
  }

  .hero {
    padding: 80px 0;
    text-align: center;
    background: url('https://images.gptkong.com/demo/sample1.png') center/cover no-repeat;
    position: relative;
    margin-bottom: 60px;
  }

  .hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(30, 39, 59, 0.8) 0%, rgba(101, 31, 255, 0.6) 100%);
  }

  .hero-content {
    position: relative;
    z-index: 1;
    max-width: 800px;
    margin: 0 auto;
  }

  .hero h1 {
    font-size: 2.5rem;
    margin-bottom: var(--spacing);
    color: var(--light);
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
  }

  .hero p {
    font-size: 1.2rem;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: calc(var(--spacing) * 1.5);
  }

  .btn {
    display: inline-block;
    padding: 12px 24px;
    background-color: var(--secondary);
    color: var(--light);
    border: none;
    border-radius: var(--border-radius);
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
  }

  .btn:hover {
    background-color: var(--accent);
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.3);
  }

  .notice {
    background-color: var(--light);
    padding: 15px;
    border-radius: var(--border-radius);
    margin: 40px auto;
    max-width: 800px;
    text-align: center;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    border-left: 4px solid var(--secondary);
  }

  article {
    background-color: var(--light);
    padding: 40px;
    border-radius: var(--border-radius);
    margin-bottom: 60px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  }

  article h2 {
    font-size: 2rem;
    color: var(--primary);
    margin-bottom: 30px;
    position: relative;
    padding-bottom: 15px;
  }

  article h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 80px;
    height: 4px;
    background: linear-gradient(90deg, var(--secondary), var(--accent));
    border-radius: 2px;
  }

  article h3 {
    font-size: 1.5rem;
    color: var(--primary);
    margin: 30px 0 20px;
  }

  article p {
    margin-bottom: 20px;
    font-size: 1.1rem;
    color: var(--dark);
  }

  pre {
    background-color: var(--primary);
    color: var(--light);
    padding: 20px;
    border-radius: var(--border-radius);
    margin: 20px 0;
    overflow-x: auto;
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
    line-height: 1.5;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
  }

  code {
    font-family: 'Courier New', monospace;
    background-color: rgba(101, 31, 255, 0.1);
    padding: 2px 4px;
    border-radius: 3px;
    color: var(--secondary);
  }

  .image-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing);
    margin: 40px 0;
  }

  .image-card {
    position: relative;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    transition: var(--transition);
  }

  .image-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
  }

  .image-card img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition);
  }

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

  .image-card::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(to top, rgba(30, 39, 59, 0.7) 0%, transparent 50%);
  }

  footer {
    background-color: var(--primary);
    color: var(--light);
    padding: 40px 0;
    text-align: center;
  }

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

  .footer-links {
    display: flex;
    justify-content: center;
    gap: var(--spacing);
    margin-bottom: var(--spacing);
  }

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

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

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

  @media (max-width: 768px) {
    .header-content {
      flex-direction: column;
      gap: var(--spacing);
    }

    .nav-links {
      flex-wrap: wrap;
      justify-content: center;
    }

    .hero h1 {
      font-size: 2rem;
    }

    article {
      padding: 30px 20px;
    }

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

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

  .fade-in {
    animation: fadeIn 0.6s ease forwards;
  }

  .delay-1 { animation-delay: 0.2s; }
  .delay-2 { animation-delay: 0.4s; }
  .delay-3 { animation-delay: 0.6s; }

  /* Theme toggle */
  .theme-toggle {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background-color: var(--secondary);
    border: none;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
    transition: var(--transition);
    z-index: 100;
  }

  .theme-toggle:hover {
    background-color: var(--accent);
    transform: scale(1.1);
  }

  .theme-toggle i {
    color: var(--light);
    font-size: 1.2rem;
  }

  /* Dark theme */
  body.dark-theme {
    background: linear-gradient(135deg, #121212 0%, #1E273B 100%);
    color: var(--light);
  }

  body.dark-theme article {
    background-color: rgba(30, 39, 59, 0.8);
    color: var(--light);
  }

  body.dark-theme article p {
    color: rgba(255, 255, 255, 0.9);
  }

  body.dark-theme article h2,
  body.dark-theme article h3 {
    color: var(--light);
  }

  body.dark-theme .notice {
    background-color: rgba(30, 39, 59, 0.8);
    color: var(--light);
  }

  body.dark-theme code {
    background-color: rgba(101, 31, 255, 0.2);
    color: var(--secondary);
  }