:root {
    --primary-blue: #007BFF;
    --primary-green: #28A745;
    --secondary-gray: #F8F9FA;
    --accent-orange: #FFA500;
    --background-white: #FFFFFF;
    --dark-blue: #0056b3;
    --light-blue: #e7f1ff;
    --tech-gradient: linear-gradient(135deg, #007BFF 0%, #00D4FF 100%);
    --shadow-sm: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 10px 20px rgba(0, 0, 0, 0.15);
    --shadow-lg: 0 15px 30px rgba(0, 0, 0, 0.2);
  }

  @font-face {
    font-family: 'Roboto';
    src: url('https://fonts.googleapis.com/css2?family=Roboto:wght@300;400;500;700&display=swap');
  }

  @font-face {
    font-family: 'Open Sans';
    src: url('https://fonts.googleapis.com/css2?family=Open+Sans:wght@300;400;600;700&display=swap');
  }

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

  body {
    font-family: 'Roboto', sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: var(--secondary-gray);
    overflow-x: hidden;
  }

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

  /* Header Styles */
  .header {
    background: var(--tech-gradient);
    color: white;
    padding: 2rem 0;
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-md);
  }

  .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;
    text-align: center;
    padding: 2rem;
  }

  .header h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    font-weight: 700;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
  }

  .header p {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto 2rem;
    opacity: 0.9;
  }

  .design-ref {
    background-color: rgba(255, 255, 255, 0.2);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    display: inline-block;
    font-size: 0.9rem;
    margin-top: 1rem;
    backdrop-filter: blur(5px);
  }

  /* Navigation */
  .navbar {
    position: sticky;
    top: 0;
    background-color: var(--primary-blue);
    color: white;
    padding: 1rem 0;
    z-index: 1000;
    box-shadow: var(--shadow-sm);
  }

  .nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
  }

  .nav-logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: white;
    text-decoration: none;
  }

  .nav-menu {
    display: flex;
    list-style: none;
  }

  .nav-item {
    margin-left: 2rem;
  }

  .nav-link {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
    position: relative;
    padding: 0.5rem 0;
  }

  .nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--accent-orange);
    transition: width 0.3s ease;
  }

  .nav-link:hover::after {
    width: 100%;
  }

  .hamburger {
    display: none;
    cursor: pointer;
    flex-direction: column;
    justify-content: space-between;
    width: 30px;
    height: 21px;
  }

  .hamburger span {
    display: block;
    width: 100%;
    height: 3px;
    background-color: white;
    transition: all 0.3s ease;
  }

  /* Main Content */
  .main-content {
    padding: 3rem 0;
  }

  .article-container {
    background-color: white;
    border-radius: 10px;
    box-shadow: var(--shadow-sm);
    padding: 2rem;
    margin-bottom: 3rem;
    position: relative;
    overflow: hidden;
  }

  .article-container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 5px;
    height: 100%;
    background: var(--tech-gradient);
  }

  article h2 {
    font-family: 'Open Sans', sans-serif;
    color: var(--primary-blue);
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--secondary-gray);
  }

  article h3 {
    font-family: 'Open Sans', sans-serif;
    color: var(--primary-green);
    font-size: 1.5rem;
    margin: 2rem 0 1rem;
  }

  article p {
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
    line-height: 1.7;
  }

  /* Code Blocks */
  pre {
    background-color: #f5f5f5;
    border-radius: 6px;
    padding: 1.5rem;
    margin: 1.5rem 0;
    overflow: auto;
    box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.05);
    position: relative;
  }

  pre::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 30px;
    background-color: #e0e0e0;
    border-radius: 6px 6px 0 0;
  }

  code {
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.9rem;
    color: #333;
  }

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

  .gallery-item {
    border-radius: 8px;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: all 0.3s ease;
    position: relative;
  }

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

  .gallery-item img {
    width: 100%;
    height: auto;
    display: block;
    transition: transform 0.5s ease;
  }

  .gallery-item:hover img {
    transform: scale(1.05);
  }

  /* Buttons */
  .btn {
    display: inline-block;
    padding: 0.8rem 1.5rem;
    border-radius: 4px;
    font-weight: 500;
    text-align: center;
    text-decoration: none;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
  }

  .btn-primary {
    background-color: var(--accent-orange);
    color: white;
  }

  .btn-primary:hover {
    background-color: #e69500;
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
  }

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

  .fade-in {
    animation: fadeIn 0.8s ease forwards;
  }

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

  /* Responsive Design */
  @media (max-width: 992px) {
    .header h1 {
      font-size: 2rem;
    }
  }

  @media (max-width: 768px) {
    .nav-menu {
      position: fixed;
      top: 70px;
      left: -100%;
      width: 100%;
      height: calc(100vh - 70px);
      background-color: var(--primary-blue);
      flex-direction: column;
      align-items: center;
      padding-top: 2rem;
      transition: left 0.3s ease;
    }

    .nav-menu.active {
      left: 0;
    }

    .nav-item {
      margin: 1rem 0;
    }

    .hamburger {
      display: flex;
    }

    .hamburger.active span:nth-child(1) {
      transform: translateY(9px) rotate(45deg);
    }

    .hamburger.active span:nth-child(2) {
      opacity: 0;
    }

    .hamburger.active span:nth-child(3) {
      transform: translateY(-9px) rotate(-45deg);
    }
  }

  @media (max-width: 576px) {
    .header h1 {
      font-size: 1.8rem;
    }

    .header p {
      font-size: 1rem;
    }

    article h2 {
      font-size: 1.5rem;
    }

    article h3 {
      font-size: 1.3rem;
    }

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