:root {
    --primary-color: #0074D9;
    --secondary-color: #8E44AD;
    --background-color: #F5F5F5;
    --text-color: #333333;
    --highlight-green: #2ECC71;
    --highlight-orange: #FFA726;
    --font-main: 'Roboto', sans-serif;
    --transition-speed: 0.3s;
  }

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

  body {
    background-color: var(--background-color);
    color: var(--text-color);
    font-family: var(--font-main);
    line-height: 1.6;
    overflow-x: hidden;
  }

  .container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 20px;
  }

  .header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 60px 20px;
    text-align: center;
    position: relative;
    overflow: hidden;
    border-radius: 0 0 20px 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
  }

  .header::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('https://images.gptkong.com/demo/sample1.png') center/cover no-repeat;
    opacity: 0.2;
    z-index: 0;
  }

  .header-content {
    position: relative;
    z-index: 1;
    max-width: 800px;
    margin: 0 auto;
  }

  h1 {
    font-size: 2.5rem;
    margin-bottom: 20px;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
  }

  h2 {
    font-size: 2rem;
    color: var(--primary-color);
    margin: 40px 0 20px;
    position: relative;
    padding-bottom: 10px;
  }

  h2::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
  }

  h3 {
    font-size: 1.5rem;
    color: var(--secondary-color);
    margin: 30px 0 15px;
  }

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

  .note {
    background: rgba(255, 255, 255, 0.9);
    padding: 20px;
    border-radius: 8px;
    margin: 30px auto;
    max-width: 800px;
    text-align: center;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    border-left: 4px solid var(--highlight-green);
  }

  .grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(500px, 1fr));
    gap: 30px;
    margin: 40px 0;
  }

  .card {
    background: white;
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.05);
    transition: transform var(--transition-speed) ease, box-shadow var(--transition-speed) ease;
  }

  .card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
  }

  .card-img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    border-radius: 8px;
    margin-bottom: 20px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    transition: transform var(--transition-speed) ease;
  }

  .card:hover .card-img {
    transform: scale(1.02);
  }

  pre {
    background: #2d2d2d;
    color: #f8f8f2;
    padding: 20px;
    border-radius: 8px;
    overflow-x: auto;
    margin: 20px 0;
    font-family: 'Courier New', monospace;
    font-size: 0.95rem;
    line-height: 1.5;
    position: relative;
  }

  pre::before {
    content: "CSS";
    position: absolute;
    top: 0;
    left: 0;
    background: var(--primary-color);
    color: white;
    padding: 2px 10px;
    border-radius: 0 0 5px 0;
    font-size: 0.8rem;
  }

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

  .color-sample {
    display: inline-block;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    vertical-align: middle;
    margin: 0 5px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
  }

  .gallery {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
    margin: 40px 0;
  }

  .gallery-item {
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    transition: transform var(--transition-speed) ease;
  }

  .gallery-item:hover {
    transform: scale(1.03);
  }

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

  .footer {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 40px 20px;
    text-align: center;
    margin-top: 60px;
  }

  @media (max-width: 768px) {
    .grid-container {
      grid-template-columns: 1fr;
    }
    
    h1 {
      font-size: 2rem;
    }
    
    h2 {
      font-size: 1.7rem;
    }
  }

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

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

  /* Navigation */
  .nav-links {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin: 30px 0;
    flex-wrap: wrap;
  }

  .nav-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    padding: 8px 15px;
    border-radius: 20px;
    transition: all var(--transition-speed) ease;
    background: rgba(0, 116, 217, 0.1);
  }

  .nav-link:hover {
    background: var(--primary-color);
    color: white;
  }