:root {
    --primary-color: #000000;
    --secondary-color: #ffffff;
    --accent-color: #ff6600;
    --gradient-start: #00c6ff;
    --gradient-end: #0072ff;
    --text-color: #333333;
    --light-bg: rgba(255,255,255,0.9);
    --card-shadow: 0 10px 30px 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: url('https://fonts.googleapis.com/css2?family=Roboto:wght@300;400;500;700&display=swap');
  }

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

  body {
    font-family: 'Roboto', sans-serif;
    color: var(--text-color);
    line-height: 1.6;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    background-attachment: fixed;
    overflow-x: hidden;
  }

  .container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 80px 20px;
  }

  .hero {
    height: 80vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    position: relative;
    overflow: hidden;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    color: var(--secondary-color);
    clip-path: polygon(0 0, 100% 0, 100% 90%, 0 100%);
    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: 0.1;
    z-index: 0;
  }

  .hero-content {
    position: relative;
    z-index: 1;
    max-width: 800px;
    padding: 0 20px;
  }

  h1 {
    font-size: 3.5rem;
    margin-bottom: 20px;
    text-shadow: 0 2px 10px rgba(0,0,0,0.3);
    animation: fadeIn 1s ease-out;
  }

  h2 {
    font-size: 2.5rem;
    margin: 40px 0 20px;
    color: var(--primary-color);
    position: relative;
    padding-bottom: 15px;
  }

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

  h3 {
    font-size: 1.8rem;
    margin: 30px 0 15px;
    color: var(--primary-color);
  }

  p {
    font-size: 1.1rem;
    margin-bottom: 20px;
    line-height: 1.8;
  }

  .grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(500px, 1fr));
    gap: 40px;
    margin: 40px 0;
  }

  .card {
    background: var(--light-bg);
    border-radius: 12px;
    padding: 30px;
    box-shadow: var(--card-shadow);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
  }

  .card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 35px rgba(0,0,0,0.2);
  }

  .card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 5px;
    background: linear-gradient(90deg, var(--gradient-start), var(--gradient-end));
  }

  .img-container {
    display: flex;
    justify-content: center;
    margin: 30px 0;
    gap: 20px;
    flex-wrap: wrap;
  }

  .decor-img {
    width: 320px;
    height: 320px;
    object-fit: cover;
    border-radius: 16px;
    box-shadow: 0 8px 20px rgba(0,0,0,0.15);
    transition: var(--transition);
  }

  .decor-img:hover {
    transform: scale(1.05);
    box-shadow: 0 12px 25px rgba(0,0,0,0.2);
  }

  pre {
    background: #2d2d2d;
    border-radius: 8px;
    padding: 20px;
    margin: 20px 0;
    overflow-x: auto;
    box-shadow: inset 0 0 10px rgba(0,0,0,0.5);
  }

  code {
    font-family: 'Courier New', monospace;
    color: #f8f8f2;
    font-size: 0.9rem;
    line-height: 1.5;
  }

  table {
    width: 100%;
    border-collapse: collapse;
    margin: 30px 0;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    border-radius: 8px;
    overflow: hidden;
  }

  th, td {
    padding: 15px;
    text-align: left;
    border-bottom: 1px solid #ddd;
  }

  th {
    background-color: var(--primary-color);
    color: var(--secondary-color);
    font-weight: 500;
  }

  tr:nth-child(even) {
    background-color: #f9f9f9;
  }

  tr:hover {
    background-color: #f1f1f1;
  }

  .navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: rgba(0,0,0,0.8);
    backdrop-filter: blur(10px);
    padding: 15px 40px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 1000;
    box-shadow: 0 2px 20px rgba(0,0,0,0.2);
  }

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

  .nav-links a {
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 500;
    font-size: 1.1rem;
    transition: var(--transition);
    position: relative;
  }

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

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

  .logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--secondary-color);
    text-decoration: none;
  }

  .logo span {
    color: var(--accent-color);
  }

  .reference-note {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: var(--accent-color);
    color: var(--secondary-color);
    padding: 10px 20px;
    border-radius: 30px;
    font-size: 0.9rem;
    box-shadow: 0 4px 15px rgba(255,102,0,0.3);
    z-index: 1000;
  }

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

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

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

  @media (max-width: 768px) {
    .grid-container {
      grid-template-columns: 1fr;
    }
    
    h1 {
      font-size: 2.5rem;
    }
    
    h2 {
      font-size: 2rem;
    }
    
    .hero {
      height: 60vh;
    }
    
    .nav-links {
      display: none;
    }
  }