:root {
    --primary: #1E3A8A;
    --secondary: #3B82F6;
    --accent: #10B981;
    --neutral: #F3F4F6;
    --dark: #1F2937;
    --light: #FFFFFF;
    --shadow: 0 10px 15px -3px rgba(0,0,0,0.1);
    --radius: 12px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  }

  @font-face {
    font-family: 'Inter';
    src: url('https://fonts.gstatic.com/s/inter/v12/UcCO3FwrK3iLTeHuS_fvQtMwCp50KnMw2boKoduKmMEVuLyfMZg.ttf') format('truetype');
  }

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

  body {
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
    color: var(--dark);
    background: linear-gradient(135deg, var(--neutral) 0%, #E5E7EB 100%);
    padding: 0;
    margin: 0;
    min-height: 100%;
  }

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

  .hero {
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
    padding: 80px 20px;
    text-align: center;
    border-radius: 0 0 var(--radius) var(--radius);
    margin-bottom: 60px;
    box-shadow: var(--shadow);
    position: relative;
    overflow: hidden;
  }

  .hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255,255,255,0.1) 0%, transparent 70%);
    animation: pulse 15s infinite linear;
    z-index: 0;
  }

  @keyframes pulse {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
  }

  .hero-content {
    position: relative;
    z-index: 1;
  }

  h1 {
    font-size: 3rem;
    margin-bottom: 20px;
    font-weight: 700;
    text-shadow: 0 2px 4px rgba(0,0,0,0.2);
  }

  h2 {
    font-size: 2.2rem;
    margin: 40px 0 20px;
    color: var(--primary);
    position: relative;
    padding-bottom: 10px;
  }

  h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 80px;
    height: 4px;
    background: linear-gradient(90deg, var(--accent), var(--secondary));
    border-radius: 2px;
  }

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

  p {
    font-size: 1.1rem;
    margin-bottom: 20px;
    color: var(--dark);
    line-height: 1.8;
  }

  .card {
    background: white;
    border-radius: var(--radius);
    padding: 30px;
    margin-bottom: 40px;
    box-shadow: var(--shadow);
    transition: var(--transition);
    border: 1px solid rgba(0,0,0,0.05);
  }

  .card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 25px -5px rgba(0,0,0,0.1);
  }

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

  .image-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin: 40px 0;
  }

  .image-box {
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
    aspect-ratio: 1/1;
  }

  .image-box:hover {
    transform: scale(1.05);
  }

  .image-box img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition);
  }

  .image-box:hover img {
    transform: scale(1.1);
  }

  pre {
    background: var(--dark);
    color: white;
    padding: 20px;
    border-radius: var(--radius);
    margin: 20px 0;
    overflow-x: auto;
    font-family: 'Courier New', monospace;
    font-size: 0.95rem;
    line-height: 1.5;
    position: relative;
  }

  pre::before {
    content: 'CSS';
    position: absolute;
    top: 0;
    right: 0;
    background: var(--accent);
    color: white;
    padding: 5px 10px;
    border-radius: 0 var(--radius) 0 var(--radius);
    font-size: 0.8rem;
    font-weight: bold;
  }

  code {
    font-family: 'Courier New', monospace;
    background: rgba(0,0,0,0.05);
    padding: 2px 4px;
    border-radius: 4px;
    font-size: 0.9rem;
  }

  .note {
    background: linear-gradient(135deg, rgba(30,58,138,0.1) 0%, rgba(59,130,246,0.1) 100%);
    border-left: 4px solid var(--secondary);
    padding: 20px;
    margin: 30px 0;
    border-radius: 0 var(--radius) var(--radius) 0;
  }

  .note p {
    margin: 0;
  }

  .footer {
    text-align: center;
    padding: 30px;
    background: var(--dark);
    color: white;
    margin-top: 60px;
    border-radius: var(--radius) var(--radius) 0 0;
  }

  .reference {
    background: white;
    padding: 20px;
    border-radius: var(--radius);
    margin: 40px 0;
    text-align: center;
    font-weight: bold;
    color: var(--primary);
    box-shadow: var(--shadow);
  }

  @media (max-width: 768px) {
    h1 {
      font-size: 2.2rem;
    }
    h2 {
      font-size: 1.8rem;
    }
    h3 {
      font-size: 1.5rem;
    }
    .grid {
      grid-template-columns: 1fr;
    }
  }