:root {
    --primary-color: #1E3A8A;
    --secondary-color: #3B82F6;
    --accent-color: #F97316;
    --background-color: #F5F5F5;
    --text-color: #333333;
    --light-gray: #E5E7EB;
    --dark-gray: #6B7280;
  }

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

  body {
    background: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
    padding: 0;
    margin: 0;
    overflow-x: hidden;
  }

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

  .header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 2rem 0;
    position: relative;
    overflow: hidden;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  }

  .header::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: 0.1;
    z-index: 0;
  }

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

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

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

  .notice {
    background: rgba(255, 255, 255, 0.2);
    padding: 1rem;
    border-radius: 8px;
    display: inline-block;
    margin-top: 1rem;
    backdrop-filter: blur(5px);
  }

  .nav {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-top: 2rem;
  }

  .nav-item {
    color: white;
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    transition: all 0.3s ease;
    position: relative;
  }

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

  .nav-item::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 2px;
    background: var(--accent-color);
    transition: width 0.3s ease;
  }

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

  .main-content {
    padding: 3rem 0;
  }

  article {
    background: white;
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
    margin-bottom: 3rem;
  }

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

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

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

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

  article em {
    font-style: italic;
    color: var(--dark-gray);
  }

  article color {
    color: var(--primary-color);
    font-weight: bold;
  }

  pre {
    background: #282c34;
    border-radius: 8px;
    padding: 1.5rem;
    margin: 1.5rem 0;
    overflow: auto;
    position: relative;
  }

  code {
    font-family: 'Courier New', Courier, monospace;
    color: #abb2bf;
    font-size: 0.9rem;
  }

  .code-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: rgba(0, 0, 0, 0.2);
    padding: 0.5rem 1rem;
    border-radius: 8px 8px 0 0;
    margin-bottom: -1.5rem;
    position: relative;
    z-index: 1;
  }

  .code-title {
    color: #abb2bf;
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 1px;
  }

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

  .gallery-item {
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    position: relative;
  }

  .gallery-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
  }

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

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

  .gallery-caption {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background: linear-gradient(transparent, rgba(0, 0, 0, 0.7));
    color: white;
    padding: 1rem;
    transform: translateY(100%);
    transition: transform 0.3s ease;
  }

  .gallery-item:hover .gallery-caption {
    transform: translateY(0);
  }

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

  .footer p {
    margin-bottom: 1rem;
  }

  .footer-links {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-top: 1rem;
  }

  .footer-link {
    color: white;
    text-decoration: none;
    transition: color 0.3s ease;
  }

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

  @media (max-width: 768px) {
    .header h1 {
      font-size: 2rem;
    }

    .nav {
      flex-direction: column;
      gap: 1rem;
    }

    .image-gallery {
      grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    }
  }

  @media (max-width: 480px) {
    .header h1 {
      font-size: 1.8rem;
    }

    article {
      padding: 1.5rem;
    }

    article h2 {
      font-size: 1.5rem;
    }

    article h3 {
      font-size: 1.2rem;
    }
  }

  /* Animations */
  @keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
  }

  @keyframes slideUp {
    from { transform: translateY(20px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
  }

  .animate-fade {
    animation: fadeIn 1s ease-out forwards;
  }

  .animate-slide {
    animation: slideUp 0.8s ease-out forwards;
  }

  /* Utility classes */
  .mt-1 { margin-top: 0.5rem; }
  .mt-2 { margin-top: 1rem; }
  .mt-3 { margin-top: 1.5rem; }
  .mt-4 { margin-top: 2rem; }
  .mb-1 { margin-bottom: 0.5rem; }
  .mb-2 { margin-bottom: 1rem; }
  .mb-3 { margin-bottom: 1.5rem; }
  .mb-4 { margin-bottom: 2rem; }