body {
    font-family: sans-serif;
    margin: 20px;
    background-color: #f4f4f4;
  }
  
  .container {
    max-width: 800px;
    margin: 0 auto;
    background-color: #fff;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  }
  
  h1 {
    text-align: center;
    margin-bottom: 20px;
  }
  
  .form-group {
    margin-bottom: 15px;
  }
  
  label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
  }
  
  input[type="email"],
  input[type="password"] {
    width: calc(100% - 12px);
    padding: 8px;
    border: 1px solid #ccc;
    border-radius: 4px;
    box-sizing: border-box;
  }
  
  button {
    padding: 10px 15px;
    background-color: #007bff;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 16px;
  }
  
  button:hover {
    background-color: #0056b3;
  }
  
  .error {
    color: red;
    margin-bottom: 10px;
  }
  
  #product-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
    margin-bottom: 20px;
  }
  
  .product-item {
    border: 1px solid #ddd;
    padding: 10px;
    border-radius: 4px;
    text-align: center;
  }
  
  .product-item h3 {
    margin-top: 0;
    margin-bottom: 5px;
  }
  
  .product-item p {
    margin-bottom: 10px;
  }
  
  #product-detail {
    padding: 15px;
    border: 1px solid #ddd;
    border-radius: 4px;
    margin-bottom: 20px;
  }
  
  #product-detail h3 {
    margin-top: 0;
    margin-bottom: 10px;
  }
  
  #product-detail p {
    margin-bottom: 10px;
  }
  
  #product-detail img {
    max-width: 100%;
    height: auto;
    margin-bottom: 15px;
  }