:root {
    --primary-dark: #001f3f;
    --primary-light: #0074D9;
    --accent: #FF851B;
    --neutral-light: #f8f9fa;
    --neutral-dark: #343a40;
    --text-light: #ffffff;
    --text-dark: #212529;
  }

  @import url('https://fonts.googleapis.com/css2?family=Montserrat:wght@700&family=Roboto:wght@400;500&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: linear-gradient(135deg, var(--neutral-light), #e9ecef);
    min-height: 100%;
    overflow-x: hidden;
  }

  .design-notice {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: rgba(0,0,0,0.7);
    color: white;
    padding: 10px 15px;
    border-radius: 5px;
    font-size: 14px;
    z-index: 1000;
  }

  .hero {
    position: relative;
    height: 80vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    background: linear-gradient(135deg, var(--primary-dark), var(--primary-light));
    color: var(--text-light);
    padding: 0 5%;
    margin-bottom: 60px;
  }

  .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: 0;
  }

  .hero-content {
    position: relative;
    z-index: 1;
    max-width: 800px;
    text-align: center;
  }

  .hero h1 {
    font-family: 'Montserrat', sans-serif;
    font-size: 3.5rem;
    margin-bottom: 20px;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
  }

  .hero p {
    font-size: 1.2rem;
    margin-bottom: 30px;
    opacity: 0.9;
  }

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

  article {
    background: white;
    border-radius: 10px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    padding: 40px;
    margin-bottom: 60px;
  }

  article h2 {
    font-family: 'Montserrat', sans-serif;
    color: var(--primary-dark);
    font-size: 2.2rem;
    margin-bottom: 25px;
    position: relative;
    padding-bottom: 15px;
  }

  article h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 80px;
    height: 4px;
    background: var(--accent);
    border-radius: 2px;
  }

  article h3 {
    font-family: 'Montserrat', sans-serif;
    color: var(--primary-light);
    font-size: 1.8rem;
    margin: 30px 0 20px;
  }

  article p {
    font-size: 1.1rem;
    margin-bottom: 20px;
    color: var(--text-dark);
  }

  .image-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    margin: 30px 0;
  }

  .image-card {
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
  }

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

  .image-card img {
    width: 100%;
    height: auto;
    display: block;
    border-radius: 8px;
  }

  pre {
    background: #2d2d2d;
    color: #f8f8f2;
    padding: 20px;
    border-radius: 8px;
    overflow-x: auto;
    margin: 25px 0;
    font-size: 0.95rem;
    line-height: 1.5;
    box-shadow: inset 0 0 10px rgba(0,0,0,0.3);
  }

  code {
    font-family: 'Courier New', Courier, monospace;
    background: rgba(0,0,0,0.05);
    padding: 2px 5px;
    border-radius: 3px;
    font-size: 0.9rem;
  }

  pre code {
    background: transparent;
    padding: 0;
  }

  .nav-tabs {
    position: sticky;
    top: 0;
    background: white;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    z-index: 100;
    padding: 15px 0;
    margin-bottom: 40px;
  }

  .nav-tabs ul {
    display: flex;
    justify-content: center;
    list-style: none;
    gap: 30px;
  }

  .nav-tabs a {
    text-decoration: none;
    color: var(--primary-dark);
    font-family: 'Montserrat', sans-serif;
    font-weight: 500;
    padding: 5px 10px;
    border-radius: 4px;
    transition: all 0.3s ease;
  }

  .nav-tabs a:hover {
    color: var(--accent);
    background: rgba(0,0,0,0.05);
  }

  .section-highlight {
    background: linear-gradient(135deg, rgba(0,31,63,0.05), rgba(0,116,217,0.05));
    padding: 40px;
    border-radius: 10px;
    margin: 40px 0;
    border-left: 4px solid var(--accent);
  }

  .floating-shapes {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    overflow: hidden;
    z-index: -1;
  }

  .shape {
    position: absolute;
    opacity: 0.1;
    border-radius: 50%;
    filter: blur(40px);
  }

  .shape-1 {
    width: 300px;
    height: 300px;
    background: var(--accent);
    top: -100px;
    right: -100px;
  }

  .shape-2 {
    width: 400px;
    height: 400px;
    background: var(--primary-light);
    bottom: -150px;
    left: -150px;
  }

  @media (max-width: 768px) {
    .hero h1 {
      font-size: 2.5rem;
    }

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

    article {
      padding: 25px;
    }

    article h2 {
      font-size: 1.8rem;
    }

    article h3 {
      font-size: 1.5rem;
    }

    .nav-tabs ul {
      gap: 15px;
      flex-wrap: wrap;
    }
  }

  @media (max-width: 480px) {
    .hero {
      height: 70vh;
    }

    .hero h1 {
      font-size: 2rem;
    }

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