:root {
    --primary-gradient: linear-gradient(90deg, #6370FF, #B859F4);
    --secondary-gradient: linear-gradient(90deg, #FF7D1E, #FF2D74);
    --bg-color: #F9FAFB;
    --text-primary: #2D3748;
    --text-secondary: #6B7280;
    --card-bg: #fff;
    --shadow-sm: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 12px 20px rgba(0, 0, 0, 0.2);
    --radius-sm: 8px;
    --radius-md: 12px;
    --transition: all 0.3s ease;
  }

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

  body {
    font-family: 'Roboto', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
  }

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

  /* Header */
  .header {
    background: var(--primary-gradient);
    padding: 20px 0;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  }

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

  .logo {
    font-size: 24px;
    font-weight: 700;
    color: white;
    text-decoration: none;
  }

  .nav-links {
    display: flex;
    gap: 20px;
  }

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

  .nav-link:hover {
    background: rgba(255, 255, 255, 0.2);
  }

  /* Hero */
  .hero {
    padding: 180px 0 100px;
    background: url('https://images.gptkong.com/demo/sample1.png') no-repeat right center/contain;
    min-height: 500px;
  }

  .hero-content {
    max-width: 600px;
  }

  .hero-title {
    font-size: 48px;
    margin-bottom: 20px;
    background: linear-gradient(90deg, #6370FF, #B859F4);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
  }

  .hero-subtitle {
    font-size: 20px;
    color: var(--text-secondary);
    margin-bottom: 30px;
  }

  .notice {
    background: rgba(255, 255, 255, 0.9);
    padding: 15px;
    border-radius: var(--radius-sm);
    margin-bottom: 30px;
    box-shadow: var(--shadow-sm);
    font-size: 14px;
    color: var(--text-secondary);
  }

  /* Article */
  .article-container {
    display: grid;
    grid-template-columns: 250px 1fr;
    gap: 40px;
    padding: 40px 0;
  }

  .sidebar {
    position: sticky;
    top: 100px;
    align-self: start;
  }

  .sidebar-nav {
    background: var(--card-bg);
    border-radius: var(--radius-md);
    padding: 20px;
    box-shadow: var(--shadow-sm);
  }

  .sidebar-title {
    font-size: 18px;
    margin-bottom: 15px;
    color: var(--text-primary);
    padding-bottom: 10px;
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
  }

  .sidebar-link {
    display: block;
    padding: 8px 0;
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition);
  }

  .sidebar-link:hover {
    color: var(--text-primary);
    transform: translateX(5px);
  }

  .article {
    background: var(--card-bg);
    border-radius: var(--radius-md);
    padding: 40px;
    box-shadow: var(--shadow-sm);
  }

  .article h2 {
    font-size: 32px;
    margin: 30px 0 20px;
    background: linear-gradient(90deg, #6370FF, #B859F4);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
  }

  .article h3 {
    font-size: 24px;
    margin: 25px 0 15px;
    color: var(--text-primary);
  }

  .article p {
    margin-bottom: 20px;
    font-size: 16px;
  }

  .article ol, .article ul {
    margin-bottom: 20px;
    padding-left: 20px;
  }

  .article li {
    margin-bottom: 10px;
  }

  .article strong {
    color: var(--text-primary);
  }

  .article em {
    font-style: italic;
    color: var(--text-secondary);
  }

  /* Code blocks */
  pre {
    background: #2D3748;
    border-radius: var(--radius-sm);
    padding: 20px;
    margin: 20px 0;
    overflow: auto;
  }

  code {
    font-family: 'Courier New', monospace;
    color: #E2E8F0;
    font-size: 14px;
  }

  /* Cards */
  .card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
    margin: 30px 0;
  }

  .card {
    background: var(--card-bg);
    border-radius: var(--radius-md);
    padding: 20px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
  }

  .card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
  }

  .card-img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    border-radius: var(--radius-sm);
    margin-bottom: 15px;
  }

  .card-title {
    font-size: 18px;
    margin-bottom: 10px;
  }

  .card-text {
    font-size: 14px;
    color: var(--text-secondary);
  }

  /* Footer */
  .footer {
    background: var(--primary-gradient);
    color: white;
    padding: 40px 0;
    margin-top: 60px;
  }

  .footer-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 30px;
  }

  .footer-col h3 {
    font-size: 18px;
    margin-bottom: 20px;
  }

  .footer-link {
    display: block;
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    margin-bottom: 10px;
    transition: var(--transition);
  }

  .footer-link:hover {
    color: white;
  }

  .copyright {
    text-align: center;
    margin-top: 40px;
    padding-top: 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    font-size: 14px;
  }

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

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

  /* Responsive */
  @media (max-width: 992px) {
    .article-container {
      grid-template-columns: 1fr;
    }
    
    .sidebar {
      position: static;
      margin-bottom: 30px;
    }
  }

  @media (max-width: 768px) {
    .hero {
      padding: 150px 0 80px;
      background-size: 300px;
    }
    
    .hero-title {
      font-size: 36px;
    }
    
    .hero-subtitle {
      font-size: 18px;
    }
    
    .nav-links {
      display: none;
    }
    
    .article {
      padding: 30px 20px;
    }
  }

  @media (max-width: 576px) {
    .hero {
      background: none;
      padding: 120px 0 60px;
    }
    
    .card-grid {
      grid-template-columns: 1fr;
    }
  }