body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
}
header {
  background-color: #1e88e5;
  color: white;
  padding: 10px;
  text-align: center;
}
nav a {
  margin: 0 10px;
  color: white;
  text-decoration: none;
}
main {
  padding: 20px;
}
.product {
  border: 1px solid #ccc;
  padding: 10px;
  margin-bottom: 10px;
}