:root {
    --primary: #0d47a1;
    --secondary: #424242;
    --accent: #ff6d00;
    --highlight: #4caf50;
    --light: #f5f5f5;
    --dark: #212121;
    --radius: 8px;
    --shadow: 0 4px 20px rgba(0,0,0,0.1);
    --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
  }

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

  body {
    font-family: 'Roboto', sans-serif;
    line-height: 1.6;
    color: var(--dark);
    background: linear-gradient(135deg, #f5f7fa 0%, #e4e8eb 100%);
    padding: 0;
    margin: 0;
    overflow-x: hidden;
  }

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

  header {
    background: linear-gradient(135deg, var(--primary) 0%, #1565c0 100%);
    color: white;
    padding: 2rem 0;
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow);
  }

  header::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('https://images.gptkong.com/demo/sample1.png') no-repeat;
    background-size: cover;
    opacity: 0.1;
    z-index: 0;
  }

  .header-content {
    position: relative;
    z-index: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    padding: 2rem;
  }

  .header-content h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
  }

  .header-content p {
    font-size: 1.2rem;
    max-width: 800px;
    margin-bottom: 2rem;
  }

  .notice {
    background: rgba(255,255,255,0.2);
    padding: 1rem;
    border-radius: var(--radius);
    backdrop-filter: blur(5px);
    margin-top: 2rem;
    font-size: 0.9rem;
  }

  nav {
    background: var(--secondary);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 10px rgba(0,0,0,0.2);
  }

  nav ul {
    display: flex;
    justify-content: center;
    list-style: none;
    gap: 2rem;
  }

  nav a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: var(--radius);
    transition: var(--transition);
  }

  nav a:hover {
    background: rgba(255,255,255,0.1);
  }

  main {
    padding: 3rem 0;
  }

  .grid-layout {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 2rem;
  }

  article {
    background: white;
    padding: 2rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
  }

  article h2 {
    color: var(--primary);
    margin-bottom: 1.5rem;
    font-size: 1.8rem;
    position: relative;
    padding-bottom: 0.5rem;
  }

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

  article h3 {
    color: var(--secondary);
    margin: 1.5rem 0 1rem;
    font-size: 1.4rem;
  }

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

  pre {
    background: #f8f8f8;
    padding: 1.5rem;
    border-radius: var(--radius);
    overflow-x: auto;
    margin: 1.5rem 0;
    border-left: 4px solid var(--accent);
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
    line-height: 1.5;
  }

  code {
    font-family: 'Courier New', monospace;
    background: rgba(13, 71, 161, 0.1);
    padding: 0.2rem 0.4rem;
    border-radius: 3px;
    font-size: 0.9rem;
  }

  .image-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
  }

  .image-card {
    background: white;
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
  }

  .image-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.1);
  }

  .image-card img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    border-bottom: 1px solid #eee;
  }

  .image-card .caption {
    padding: 1rem;
    text-align: center;
    color: var(--secondary);
  }

  aside {
    background: white;
    padding: 2rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    align-self: start;
    position: sticky;
    top: 100px;
  }

  aside h3 {
    color: var(--primary);
    margin-bottom: 1.5rem;
    font-size: 1.4rem;
  }

  aside ul {
    list-style: none;
  }

  aside li {
    margin-bottom: 0.8rem;
  }

  aside a {
    color: var(--secondary);
    text-decoration: none;
    transition: var(--transition);
    display: block;
    padding: 0.5rem;
    border-radius: var(--radius);
  }

  aside a:hover {
    background: rgba(13, 71, 161, 0.1);
    color: var(--primary);
  }

  footer {
    background: var(--secondary);
    color: white;
    padding: 3rem 0;
    text-align: center;
  }

  footer p {
    margin-bottom: 1rem;
  }

  .footer-links {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 2rem;
  }

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

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

  @media (max-width: 768px) {
    .grid-layout {
      grid-template-columns: 1fr;
    }

    aside {
      position: static;
      margin-bottom: 2rem;
    }

    nav ul {
      flex-direction: column;
      align-items: center;
      gap: 0.5rem;
    }

    .header-content h1 {
      font-size: 2rem;
    }
  }

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

  article {
    animation: fadeIn 0.8s ease-out;
  }

  /* Additional styling for visual hierarchy */
  .highlight-box {
    background: linear-gradient(135deg, rgba(255,109,0,0.1) 0%, rgba(76,175,80,0.1) 100%);
    padding: 2rem;
    border-radius: var(--radius);
    margin: 2rem 0;
    border-left: 4px solid var(--accent);
  }

  .tag-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin: 1rem 0;
  }

  .tag {
    background: rgba(13, 71, 161, 0.1);
    color: var(--primary);
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
  }