:root {
    --primary-color: #0A2442;
    --secondary-color: #00A8E8;
    --accent-color: #39FF14;
    --dark-bg: #0D0D0D;
    --light-bg: #1A1A1A;
    --text-color: #FFFFFF;
    --text-secondary: #CCCCCC;
    --border-radius: 12px;
    --box-shadow: 0 8px 32px rgba(0, 168, 232, 0.2);
    --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
  }

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

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

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

  body {
    font-family: 'Open Sans', sans-serif;
    background: linear-gradient(135deg, var(--dark-bg) 0%, #121212 100%);
    color: var(--text-color);
    line-height: 1.6;
    overflow-x: hidden;
    min-height: 100%;
    padding-bottom: 60px;
  }

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

  .header-banner {
    background: linear-gradient(90deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    padding: 60px 0;
    text-align: center;
    margin-bottom: 60px;
    position: relative;
    overflow: hidden;
  }

  .header-banner::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('https://images.gptkong.com/demo/sample6.png') no-repeat;
    background-size: cover;
    opacity: 0.1;
    z-index: 0;
  }

  .header-banner h1 {
    font-family: 'Montserrat', sans-serif;
    font-size: 3rem;
    margin-bottom: 20px;
    position: relative;
    z-index: 1;
    text-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
  }

  .header-banner p {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
  }

  .design-notice {
    background-color: var(--light-bg);
    padding: 15px;
    border-radius: var(--border-radius);
    margin: 30px auto;
    text-align: center;
    max-width: 800px;
    border-left: 4px solid var(--accent-color);
    box-shadow: var(--box-shadow);
  }

  article {
    background-color: var(--light-bg);
    border-radius: var(--border-radius);
    padding: 40px;
    margin-bottom: 60px;
    box-shadow: var(--box-shadow);
  }

  article h2 {
    font-family: 'Montserrat', sans-serif;
    color: var(--secondary-color);
    margin-bottom: 30px;
    font-size: 2rem;
    position: relative;
    padding-bottom: 15px;
  }

  article h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 80px;
    height: 3px;
    background: linear-gradient(90deg, var(--secondary-color) 0%, var(--accent-color) 100%);
  }

  article h3 {
    font-family: 'Montserrat', sans-serif;
    color: var(--secondary-color);
    margin: 30px 0 20px;
    font-size: 1.5rem;
  }

  article h4 {
    font-family: 'Montserrat', sans-serif;
    color: var(--text-color);
    margin: 25px 0 15px;
    font-size: 1.2rem;
  }

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

  article strong {
    color: var(--text-color);
  }

  .image-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin: 40px 0;
  }

  .image-card {
    background: linear-gradient(135deg, #1E1E1E 0%, #2A2A2A 100%);
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
    transition: var(--transition);
  }

  .image-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 12px 28px rgba(0, 168, 232, 0.3);
  }

  .image-card img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    border-bottom: 2px solid var(--secondary-color);
  }

  .image-card .caption {
    padding: 20px;
    text-align: center;
  }

  pre {
    background: #1E1E1E;
    border-radius: var(--border-radius);
    padding: 20px;
    margin: 25px 0;
    overflow-x: auto;
    box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.5);
    border-left: 4px solid var(--accent-color);
  }

  code {
    font-family: 'Courier New', monospace;
    color: #E6DB74;
    font-size: 0.95rem;
  }

  .code-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: #252525;
    padding: 8px 15px;
    border-radius: var(--border-radius) var(--border-radius) 0 0;
    margin-bottom: -10px;
    color: var(--text-secondary);
    font-size: 0.9rem;
  }

  .nav-tabs {
    display: flex;
    list-style: none;
    margin-bottom: 30px;
    border-bottom: 1px solid #333;
  }

  .nav-tabs li {
    margin-right: 15px;
  }

  .nav-tabs a {
    display: block;
    padding: 10px 20px;
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: var(--border-radius) var(--border-radius) 0 0;
    transition: var(--transition);
    position: relative;
  }

  .nav-tabs a:hover {
    color: var(--text-color);
  }

  .nav-tabs a.active {
    color: var(--secondary-color);
    background: rgba(0, 168, 232, 0.1);
  }

  .nav-tabs a.active::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--secondary-color);
  }

  .accordion {
    margin: 30px 0;
  }

  .accordion-item {
    margin-bottom: 15px;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  }

  .accordion-header {
    background: linear-gradient(90deg, var(--primary-color) 0%, #142848 100%);
    padding: 15px 20px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: var(--transition);
  }

  .accordion-header:hover {
    background: linear-gradient(90deg, #142848 0%, #1A365D 100%);
  }

  .accordion-content {
    background-color: #252525;
    padding: 0;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
  }

  .accordion-content-inner {
    padding: 20px;
  }

  .accordion-item.active .accordion-content {
    max-height: 1000px;
  }

  .footer {
    text-align: center;
    padding: 30px 0;
    color: var(--text-secondary);
    font-size: 0.9rem;
  }

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

    article {
      padding: 25px;
    }

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

  /* Animations */
  @keyframes float {
    0%, 100% {
      transform: translateY(0);
    }
    50% {
      transform: translateY(-15px);
    }
  }

  .floating {
    animation: float 4s ease-in-out infinite;
  }

  @keyframes pulse {
    0%, 100% {
      opacity: 1;
    }
    50% {
      opacity: 0.6;
    }
  }

  .pulse {
    animation: pulse 2s ease-in-out infinite;
  }

  /* Scroll indicator */
  .scroll-indicator {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background-color: var(--secondary-color);
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    opacity: 0;
    transition: var(--transition);
    z-index: 100;
    box-shadow: 0 4px 15px rgba(0, 168, 232, 0.4);
  }

  .scroll-indicator.visible {
    opacity: 1;
  }

  .scroll-indicator svg {
    width: 24px;
    height: 24px;
    fill: white;
  }