:root {
    --primary: #4b6cb7;
    --secondary: #182848;
    --accent: #ff7e5f;
    --text: #f0f0f0;
    --card-bg: rgba(255, 255, 255, 0.1);
    --transition: all 0.3s ease;
  }

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

  body {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: var(--text);
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    overflow-x: hidden;
  }

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

  /* Header */
  header {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(24, 40, 72, 0.8);
    backdrop-filter: blur(10px);
    z-index: 1000;
    padding: 15px 0;
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.1);
  }

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

  .logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: white;
    text-decoration: none;
  }

  .nav-links {
    display: flex;
    gap: 30px;
  }

  .nav-links a {
    color: white;
    text-decoration: none;
    transition: var(--transition);
    position: relative;
  }

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

  .nav-links a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent);
    transition: var(--transition);
  }

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

  /* Hero Section */
  .hero {
    height: 80vh;
    display: flex;
    align-items: center;
    position: relative;
    margin-top: 70px;
  }

  .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-content {
    max-width: 600px;
  }

  .hero h1 {
    font-size: 3rem;
    margin-bottom: 20px;
    line-height: 1.2;
  }

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

  /* Main Content */
  main {
    padding: 80px 0;
  }

  section {
    margin-bottom: 80px;
    scroll-margin-top: 100px;
  }

  h2 {
    font-size: 2.2rem;
    margin-bottom: 30px;
    color: white;
    position: relative;
    display: inline-block;
  }

  h2::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 0;
    width: 50%;
    height: 3px;
    background: linear-gradient(90deg, var(--accent), transparent);
  }

  h3 {
    font-size: 1.8rem;
    margin: 30px 0 20px;
    color: white;
  }

  p {
    margin-bottom: 20px;
    font-size: 1.1rem;
  }

  /* Cards */
  .card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-top: 40px;
  }

  .card {
    background: var(--card-bg);
    border-radius: 15px;
    padding: 30px;
    backdrop-filter: blur(8px);
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.1);
    transition: var(--transition);
    border: 1px solid rgba(255, 255, 255, 0.1);
  }

  .card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.2);
  }

  .card-img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    border-radius: 10px;
    margin-bottom: 20px;
    transition: var(--transition);
  }

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

  /* Code Blocks */
  pre {
    background: rgba(0, 0, 0, 0.3);
    border-radius: 10px;
    padding: 20px;
    margin: 30px 0;
    overflow: auto;
    border-left: 4px solid var(--accent);
  }

  code {
    font-family: 'Courier New', Courier, monospace;
    color: #f8f8f2;
  }

  /* Tables */
  table {
    width: 100%;
    border-collapse: collapse;
    margin: 30px 0;
    background: var(--card-bg);
    backdrop-filter: blur(8px);
    border-radius: 10px;
    overflow: hidden;
  }

  th, td {
    padding: 15px;
    text-align: left;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  }

  th {
    background: rgba(0, 0, 0, 0.2);
    font-weight: bold;
  }

  tr:hover {
    background: rgba(255, 255, 255, 0.05);
  }

  /* Buttons */
  .btn {
    display: inline-block;
    padding: 12px 25px;
    border-radius: 5px;
    text-decoration: none;
    font-weight: bold;
    transition: var(--transition);
    border: none;
    cursor: pointer;
  }

  .btn-primary {
    background: linear-gradient(45deg, var(--accent), #feb47b);
    color: white;
  }

  .btn-primary:hover {
    background: linear-gradient(45deg, #feb47b, var(--accent));
    box-shadow: 0 10px 20px rgba(255, 126, 95, 0.4);
  }

  .btn-secondary {
    background: transparent;
    border: 2px solid white;
    color: white;
  }

  .btn-secondary:hover {
    background: white;
    color: var(--secondary);
  }

  /* Footer */
  footer {
    background: rgba(0, 0, 0, 0.3);
    padding: 40px 0;
    text-align: center;
    backdrop-filter: blur(10px);
  }

  .footer-text {
    margin-bottom: 20px;
  }

  .social-links {
    display: flex;
    justify-content: center;
    gap: 20px;
  }

  .social-links a {
    color: white;
    font-size: 1.5rem;
    transition: var(--transition);
  }

  .social-links a:hover {
    color: var(--accent);
    transform: translateY(-3px);
  }

  /* Animations */
  @keyframes float {
    0%, 100% {
      transform: translateY(0);
    }
    50% {
      transform: translateY(-10px);
    }
  }

  .floating {
    animation: float 3s ease-in-out infinite;
  }

  /* Responsive */
  @media (max-width: 768px) {
    .nav-container {
      flex-direction: column;
      gap: 20px;
    }

    .hero h1 {
      font-size: 2.2rem;
    }

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

    h2 {
      font-size: 1.8rem;
    }

    h3 {
      font-size: 1.5rem;
    }
  }

  /* Scroll Animation */
  .scroll-animation {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease-out, transform 0.6s ease-out;
  }

  .scroll-animation.visible {
    opacity: 1;
    transform: translateY(0);
  }

  /* Reference Note */
  .reference {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: rgba(0, 0, 0, 0.5);
    padding: 10px 15px;
    border-radius: 5px;
    font-size: 0.8rem;
    backdrop-filter: blur(5px);
    z-index: 1000;
  }