:root {
    --primary-color: #0A2D4C;
    --secondary-color: #F1F3F5;
    --accent-color: #FF7E00;
    --text-color: #333;
    --light-text: #fff;
    --card-bg: rgba(255, 255, 255, 0.9);
    --section-spacing: 80px;
    --border-radius: 12px;
    --box-shadow: 0 12px 24px rgba(0, 0, 0, 0.1);
  }

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

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

  body {
    font-family: 'Montserrat', sans-serif;
    color: var(--text-color);
    background: linear-gradient(135deg, var(--secondary-color) 0%, var(--primary-color) 100%);
    line-height: 1.6;
    overflow-x: hidden;
  }

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

  header {
    background: rgba(10, 45, 76, 0.9);
    padding: 20px 0;
    position: fixed;
    width: 100%;
    z-index: 1000;
    backdrop-filter: blur(10px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  }

  .header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
  }

  .logo {
    font-size: 24px;
    font-weight: 700;
    color: var(--light-text);
    text-decoration: none;
    display: flex;
    align-items: center;
  }

  .logo-icon {
    margin-right: 10px;
    width: 32px;
    height: 32px;
    background-color: var(--accent-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
  }

  nav ul {
    display: flex;
    list-style: none;
  }

  nav ul li {
    margin-left: 30px;
  }

  nav ul li a {
    color: var(--light-text);
    text-decoration: none;
    font-weight: 600;
    transition: color 0.3s ease;
    position: relative;
  }

  nav ul li a:hover {
    color: var(--accent-color);
  }

  nav ul li a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--accent-color);
    transition: width 0.3s ease;
  }

  nav ul li a:hover::after {
    width: 100%;
  }

  .hero {
    padding: 180px 0 100px;
    text-align: center;
    position: relative;
    overflow: hidden;
  }

  .hero::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: -1;
  }

  .hero h1 {
    font-size: 48px;
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--light-text);
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
  }

  .hero p {
    font-size: 20px;
    max-width: 800px;
    margin: 0 auto 40px;
    color: var(--light-text);
  }

  .cta-button {
    display: inline-block;
    background-color: var(--accent-color);
    color: var(--light-text);
    padding: 15px 30px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    box-shadow: 0 4px 12px rgba(255, 126, 0, 0.3);
  }

  .cta-button:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(255, 126, 0, 0.4);
  }

  .section {
    padding: var(--section-spacing) 0;
  }

  .section-title {
    text-align: center;
    margin-bottom: 60px;
    position: relative;
  }

  .section-title h2 {
    font-size: 36px;
    font-weight: 700;
    color: var(--primary-color);
    display: inline-block;
    padding-bottom: 15px;
  }

  .section-title h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 3px;
    background-color: var(--accent-color);
  }

  .features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
  }

  .feature-card {
    background-color: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 30px;
    box-shadow: var(--box-shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    text-align: center;
  }

  .feature-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 16px 32px rgba(0, 0, 0, 0.15);
  }

  .feature-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 20px;
    background-color: rgba(255, 126, 0, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
  }

  .feature-icon img {
    width: 40px;
    height: 40px;
  }

  .feature-card h3 {
    font-size: 22px;
    margin-bottom: 15px;
    color: var(--primary-color);
  }

  .image-gallery {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin: 40px 0;
  }

  .gallery-item {
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--box-shadow);
    transition: transform 0.3s ease;
  }

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

  .gallery-item img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    display: block;
    transition: transform 0.5s ease;
  }

  .gallery-item:hover img {
    transform: scale(1.1);
  }

  article {
    background-color: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 40px;
    box-shadow: var(--box-shadow);
    margin: 40px 0;
  }

  article h2 {
    font-size: 32px;
    color: var(--primary-color);
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 2px solid var(--accent-color);
  }

  article h3 {
    font-size: 24px;
    color: var(--primary-color);
    margin: 30px 0 15px;
  }

  article p {
    margin-bottom: 20px;
    font-size: 16px;
    line-height: 1.7;
  }

  pre {
    background-color: #f5f5f5;
    border-radius: var(--border-radius);
    padding: 20px;
    overflow-x: auto;
    margin: 20px 0;
    box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.1);
  }

  code {
    font-family: 'Courier New', monospace;
    font-size: 14px;
    color: #333;
  }

  ol {
    margin-left: 20px;
    margin-bottom: 20px;
  }

  ol li {
    margin-bottom: 10px;
  }

  ol li strong {
    color: var(--primary-color);
  }

  .tech-showcase {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    margin: 30px 0;
  }

  .tech-item {
    flex: 1 1 200px;
    background-color: rgba(10, 45, 76, 0.1);
    border-radius: var(--border-radius);
    padding: 20px;
    text-align: center;
    transition: all 0.3s ease;
  }

  .tech-item:hover {
    background-color: rgba(10, 45, 76, 0.2);
    transform: translateY(-5px);
  }

  .tech-item img {
    width: 60px;
    height: 60px;
    margin-bottom: 10px;
  }

  footer {
    background-color: var(--primary-color);
    color: var(--light-text);
    padding: 40px 0;
    text-align: center;
  }

  .footer-links {
    display: flex;
    justify-content: center;
    margin-bottom: 20px;
  }

  .footer-links a {
    color: var(--light-text);
    margin: 0 15px;
    text-decoration: none;
    transition: color 0.3s ease;
  }

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

  .copyright {
    opacity: 0.8;
    font-size: 14px;
  }

  .reference-note {
    background-color: rgba(255, 255, 255, 0.2);
    padding: 10px;
    border-radius: 5px;
    text-align: center;
    margin: 20px 0;
    font-size: 14px;
    color: var(--light-text);
  }

  @media (max-width: 768px) {
    .hero h1 {
      font-size: 36px;
    }

    .hero p {
      font-size: 18px;
    }

    nav ul {
      display: none;
    }

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

    .section-title h2 {
      font-size: 28px;
    }

    article h2 {
      font-size: 28px;
    }

    article h3 {
      font-size: 22px;
    }
  }

  /* 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;
  }

  /* Tooltip */
  .tooltip {
    position: relative;
    display: inline-block;
  }

  .tooltip .tooltiptext {
    visibility: hidden;
    width: 200px;
    background-color: var(--primary-color);
    color: var(--light-text);
    text-align: center;
    border-radius: 6px;
    padding: 10px;
    position: absolute;
    z-index: 1;
    bottom: 125%;
    left: 50%;
    transform: translateX(-50%);
    opacity: 0;
    transition: opacity 0.3s;
  }

  .tooltip:hover .tooltiptext {
    visibility: visible;
    opacity: 1;
  }