* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  
  html {
    scroll-behavior: smooth;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  }
  
  body {
    background-color: #fff;
    color: #000;
    line-height: 1.6;
  }
  
  header {
    background: linear-gradient(to right, #667eea, #764ba2);
    color: #fff;
    padding: 4rem 2rem;
    text-align: center;
  }
  
  nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 4rem;
    flex-wrap: wrap;
  }
  
  .logo {
    font-size: 1.5rem;
    font-weight: bold;
  }
  
  nav ul {
    display: flex;
    gap: 1.5rem;
    list-style: none;
  }
  
  nav a {
    color: #fff;
    text-decoration: none;
    font-weight: 500;
  }
  
  .hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
  }
  
  .hero p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
  }
  
  .btn {
    background-color: #fff;
    color: #764ba2;
    padding: 0.8rem 1.8rem;
    border-radius: 30px;
    text-decoration: none;
    font-weight: 600;
    transition: background-color 0.3s ease;
  }
  
  .btn:hover {
    background-color: #ddd;
  }
  
  .section {
    padding: 5rem 2rem;
    text-align: center;
  }
  
  .section.dark {
    background-color: #f5f5f7;
  }
  
  .grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
  }
  
  .card {
    background-color: #fff;
    border-radius: 20px;
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.05);
    padding: 2rem;
    text-align: center;
  }
  
  .card img {
    width: 100%;
    border-radius: 10px;
    margin-bottom: 1rem;
  }
  
  .responsive-img {
    width: 100%;
    max-width: 800px;
    border-radius: 10px;
    margin-top: 2rem;
    box-shadow: 0 6px 15px rgba(0,0,0,0.1);
  }
  
  footer {
    background: #000;
    color: #fff;
    text-align: center;
    padding: 2rem;
    font-size: 0.9rem;
  }