body {
  font-family: Arial, sans-serif;
  margin: 0;
  background-color: #f5f5f5;
}

nav {
  background-color: #333;
  padding: 12px;
}

nav a {
  color: white;
  margin-right: 15px;
  text-decoration: none;
  font-weight: bold;
}

main {
  padding: 20px;
}

.card {
  background: white;
  padding: 15px;
  margin-bottom: 15px;
  border-radius: 5px;
}