body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  
  header {
    background-color: #333;
    color: white;
    padding: 10px;
  }
  
  nav a {
    color: white;
    text-decoration: none;
    margin-right: 10px;
  }
  
  main {
    padding: 20px;
  }
  
  .category, .item {
    border: 1px solid #ccc;
    padding: 10px;
    margin: 10px 0;
  }
  
  .item img {
    display: block;
    max-width: 100%;
    height: auto;
  }