:root {
    --primary: linear-gradient(135deg, #1E90FF, #8A2BE2);
    --secondary: #F5F5F5;
    --accent: #FF8C00;
    --text: #333;
    --light: #FFF;
    --shadow: 0 4px 20px rgba(0,0,0,0.1);
  }

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

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

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

  .header-banner {
    background: var(--primary);
    color: var(--light);
    padding: 80px 0;
    text-align: center;
    position: relative;
    overflow: hidden;
    border-radius: 0 0 40px 40px;
    box-shadow: var(--shadow);
    margin-bottom: 60px;
  }

  .header-banner::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: 0.2;
    z-index: 0;
  }

  .header-banner h1 {
    font-size: 3rem;
    margin-bottom: 20px;
    position: relative;
    z-index: 1;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
  }

  .header-banner p {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
  }

  .design-ref {
    background: var(--accent);
    color: var(--light);
    padding: 10px 20px;
    border-radius: 30px;
    display: inline-block;
    margin-top: 30px;
    font-weight: bold;
    position: relative;
    z-index: 1;
    box-shadow: 0 4px 15px rgba(255,140,0,0.3);
  }

  .article-container {
    display: grid;
    grid-template-columns: 1fr 300px;
    gap: 40px;
    margin-bottom: 60px;
  }

  article {
    background: var(--light);
    padding: 40px;
    border-radius: 20px;
    box-shadow: var(--shadow);
  }

  article h2 {
    font-size: 2rem;
    margin-bottom: 30px;
    color: #1E90FF;
    position: relative;
    padding-bottom: 15px;
  }

  article h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100px;
    height: 4px;
    background: var(--primary);
    border-radius: 2px;
  }

  article h3 {
    font-size: 1.5rem;
    margin: 30px 0 20px;
    color: #8A2BE2;
  }

  article p {
    margin-bottom: 20px;
    font-size: 1.1rem;
  }

  article code {
    background: rgba(30, 144, 255, 0.1);
    padding: 2px 5px;
    border-radius: 3px;
    font-family: monospace;
  }

  pre {
    background: #282c34;
    color: #abb2bf;
    padding: 20px;
    border-radius: 8px;
    overflow-x: auto;
    margin: 25px 0;
    box-shadow: inset 0 0 10px rgba(0,0,0,0.5);
  }

  pre code {
    background: transparent;
    padding: 0;
    border-radius: 0;
    font-size: 0.9rem;
    line-height: 1.5;
  }

  .sidebar {
    position: sticky;
    top: 20px;
    align-self: start;
  }

  .nav-card {
    background: var(--light);
    padding: 20px;
    border-radius: 15px;
    box-shadow: var(--shadow);
    margin-bottom: 20px;
  }

  .nav-card h3 {
    font-size: 1.2rem;
    margin-bottom: 15px;
    color: #1E90FF;
  }

  .nav-card ul {
    list-style: none;
  }

  .nav-card li {
    margin-bottom: 10px;
  }

  .nav-card a {
    color: var(--text);
    text-decoration: none;
    transition: color 0.3s;
    display: block;
    padding: 8px 0;
    border-bottom: 1px solid rgba(0,0,0,0.1);
  }

  .nav-card a:hover {
    color: var(--accent);
  }

  .image-gallery {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
    margin-top: 20px;
  }

  .gallery-img {
    width: 100%;
    height: 140px;
    object-fit: cover;
    border-radius: 10px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.1);
    transition: transform 0.3s, box-shadow 0.3s;
  }

  .gallery-img:hover {
    transform: scale(1.05);
    box-shadow: 0 8px 20px rgba(0,0,0,0.2);
  }

  table {
    width: 100%;
    border-collapse: collapse;
    margin: 25px 0;
    background: var(--light);
    border-radius: 10px;
    overflow: hidden;
    box-shadow: var(--shadow);
  }

  th, td {
    padding: 15px;
    text-align: left;
    border-bottom: 1px solid rgba(0,0,0,0.1);
  }

  th {
    background: rgba(30, 144, 255, 0.1);
    color: #1E90FF;
    font-weight: bold;
  }

  tr:hover {
    background: rgba(30, 144, 255, 0.05);
  }

  ol, ul {
    padding-left: 25px;
    margin: 20px 0;
  }

  li {
    margin-bottom: 10px;
  }

  @media (max-width: 900px) {
    .article-container {
      grid-template-columns: 1fr;
    }
    
    .sidebar {
      position: static;
      order: -1;
    }
  }

  @media (max-width: 600px) {
    .header-banner h1 {
      font-size: 2rem;
    }
    
    article {
      padding: 25px;
    }
    
    .image-gallery {
      grid-template-columns: 1fr;
    }
  }

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

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