body {
  margin: 0;
  font-family: Arial, sans-serif;
  background-color: #f9fdf9;
  color: #1b5e20;
}
header {
  background: #008000;
  color: white;
  padding: 1rem;
  text-align: center;
}
nav a {
  margin: 0 1rem;
  color: white;
  text-decoration: none;
}
.card {
  background: white;
  border-radius: 12px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
  padding: 1rem;
  margin: 1rem;
  text-align: center;
}
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
}