:root {
    --primary: #1E3A8A;
    --secondary: #F47216;
    --bg-light: #F9FAFB;
    --text-dark: #1F2937;
    --text-light: #FFFFFF;
    --accent: #10B981;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
  }

  @font-face {
    font-family: 'Roboto';
    src: local('Roboto'), local('Roboto-Regular');
    font-weight: 400;
    font-display: swap;
  }

  @font-face {
    font-family: 'Roboto';
    src: local('Roboto Bold'), local('Roboto-Bold');
    font-weight: 700;
    font-display: swap;
  }

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

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

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

  /* Header Styles */
  header {
    background: linear-gradient(135deg, var(--primary) 0%, #0F2C6B 100%);
    color: var(--text-light);
    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 center right;
    background-size: contain;
    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: 3rem 0;
  }

  .header-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
    background: linear-gradient(to right, var(--text-light), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
  }

  .header-subtitle {
    font-size: 1.25rem;
    max-width: 800px;
    margin-bottom: 2rem;
    opacity: 0.9;
  }

  .notice {
    background: rgba(255, 255, 255, 0.2);
    padding: 1rem;
    border-radius: 8px;
    margin-top: 2rem;
    font-size: 0.9rem;
    backdrop-filter: blur(5px);
  }

  /* Navigation */
  nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    background: rgba(30, 58, 138, 0.9);
    position: sticky;
    top: 0;
    z-index: 1000;
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  }

  .nav-links {
    display: flex;
    gap: 2rem;
  }

  .nav-links a {
    color: var(--text-light);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    position: relative;
    padding: 0.5rem 0;
  }

  .nav-links a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--secondary);
    transition: var(--transition);
  }

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

  /* Main Content */
  main {
    padding: 4rem 0;
  }

  article {
    background: white;
    border-radius: 12px;
    box-shadow: var(--shadow);
    padding: 3rem;
    margin-bottom: 3rem;
  }

  article h2 {
    font-size: 2rem;
    color: var(--primary);
    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: var(--secondary);
  }

  article h3 {
    font-size: 1.5rem;
    color: var(--primary);
    margin: 2rem 0 1rem;
  }

  article p {
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
    line-height: 1.8;
  }

  article img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    box-shadow: var(--shadow);
    margin: 2rem auto;
    display: block;
    transition: var(--transition);
  }

  article img:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.15);
  }

  /* Code Blocks */
  pre {
    background: #282C34;
    border-radius: 8px;
    padding: 1.5rem;
    margin: 2rem 0;
    overflow: auto;
    position: relative;
  }

  pre::before {
    content: 'CSS';
    position: absolute;
    top: 0;
    left: 0;
    background: var(--secondary);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 0 0 8px 0;
    font-size: 0.8rem;
    font-weight: bold;
  }

  code {
    font-family: 'Courier New', Courier, monospace;
    color: #ABB2BF;
    font-size: 0.95rem;
    line-height: 1.5;
  }

  /* Image Grid */
  .image-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin: 3rem 0;
  }

  .image-grid img {
    width: 100%;
    height: 300px;
    object-fit: cover;
    border-radius: 12px;
    transition: var(--transition);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
  }

  .image-grid img:hover {
    transform: scale(1.03);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
  }

  /* Footer */
  footer {
    background: linear-gradient(135deg, var(--primary) 0%, #0F2C6B 100%);
    color: var(--text-light);
    padding: 3rem 0;
    text-align: center;
  }

  .footer-content {
    max-width: 800px;
    margin: 0 auto;
  }

  .footer-links {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin: 1.5rem 0;
  }

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

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

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

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

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

  /* Responsive */
  @media (max-width: 768px) {
    .header-title {
      font-size: 2.2rem;
    }

    .nav-links {
      gap: 1rem;
    }

    article {
      padding: 2rem;
    }

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

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

    .nav-links {
      flex-direction: column;
      gap: 0.5rem;
    }

    article {
      padding: 1.5rem;
    }
  }