:root {
    --primary: #032B44;
    --secondary-1: #81C784;
    --secondary-2: #FF9800;
    --neutral-1: #F5F5F5;
    --neutral-2: #FFFFFF;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
  }

  * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Roboto', sans-serif;
  }

  body {
    background-color: var(--neutral-1);
    color: #333;
    line-height: 1.6;
    min-height: 100%;
    overflow-x: hidden;
  }

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

  .header {
    background: linear-gradient(135deg, var(--primary), #0a4b78);
    color: white;
    padding: 2rem 0;
    position: relative;
    overflow: hidden;
    margin-bottom: 3rem;
  }

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

  .header-content {
    position: relative;
    z-index: 1;
    text-align: center;
    padding: 2rem;
  }

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

  .header p {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto 2rem;
  }

  .reference-banner {
    background-color: var(--secondary-2);
    color: white;
    padding: 0.5rem;
    text-align: center;
    font-size: 0.9rem;
    position: sticky;
    top: 0;
    z-index: 100;
  }

  .main-content {
    display: grid;
    grid-template-columns: 250px 1fr;
    gap: 2rem;
    margin-bottom: 3rem;
  }

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

  .sidebar {
    background-color: var(--neutral-2);
    border-radius: 8px;
    padding: 1.5rem;
    box-shadow: var(--shadow);
    height: fit-content;
    position: sticky;
    top: 40px;
  }

  .sidebar h3 {
    color: var(--primary);
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--secondary-1);
  }

  .sidebar-nav {
    list-style: none;
  }

  .sidebar-nav li {
    margin-bottom: 0.5rem;
  }

  .sidebar-nav a {
    display: block;
    padding: 0.5rem;
    color: #555;
    text-decoration: none;
    transition: all 0.3s ease;
    border-radius: 4px;
  }

  .sidebar-nav a:hover {
    background-color: var(--neutral-1);
    color: var(--primary);
    transform: translateX(5px);
  }

  .article-content {
    background-color: var(--neutral-2);
    border-radius: 8px;
    padding: 2rem;
    box-shadow: var(--shadow);
  }

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

  .article-content h2::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, var(--secondary-1), var(--secondary-2));
  }

  .article-content h3 {
    color: var(--primary);
    margin: 2rem 0 1rem;
    font-size: 1.4rem;
  }

  .article-content h4 {
    color: var(--primary);
    margin: 1.5rem 0 0.8rem;
    font-size: 1.2rem;
  }

  .article-content p {
    margin-bottom: 1.2rem;
    font-size: 1.05rem;
  }

  .article-content img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    margin: 1.5rem auto;
    display: block;
    transition: transform 0.3s ease;
  }

  .article-content img:hover {
    transform: scale(1.02);
  }

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

  .image-grid img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    border-radius: 8px;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    transition: all 0.3s ease;
  }

  .image-grid img:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 16px rgba(0,0,0,0.15);
  }

  pre {
    background-color: #f8f8f8;
    border-radius: 6px;
    padding: 1.2rem;
    overflow-x: auto;
    margin: 1.5rem 0;
    border-left: 4px solid var(--secondary-1);
    font-size: 0.95rem;
    line-height: 1.5;
  }

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

  .color-swatch {
    display: inline-block;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    vertical-align: middle;
    margin: 0 5px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  }

  .card {
    background-color: var(--neutral-2);
    border-radius: 8px;
    padding: 1.5rem;
    margin: 1.5rem 0;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
  }

  .card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.12);
  }

  .footer {
    background: linear-gradient(135deg, var(--primary), #0a4b78);
    color: white;
    padding: 2rem 0;
    text-align: center;
    margin-top: 3rem;
  }

  .footer p {
    margin-bottom: 0.5rem;
  }

  .footer a {
    color: var(--secondary-1);
    text-decoration: none;
    transition: color 0.3s ease;
  }

  .footer a:hover {
    color: var(--secondary-2);
  }

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

  .floating-element {
    animation: float 4s ease-in-out infinite;
  }

  @media (max-width: 600px) {
    .header h1 {
      font-size: 2rem;
    }
    
    .header p {
      font-size: 1rem;
    }
    
    .article-content {
      padding: 1.5rem;
    }
    
    pre {
      font-size: 0.85rem;
      padding: 1rem;
    }
  }