body {
  font-family: Arial, sans-serif;
  margin: 0;
  line-height: 1.6;
}
header {
  background: #1f2937;
  color: white;
  padding: 1rem;
}
nav a {
  color: white;
  margin-right: 15px;
  text-decoration: none;
}
section {
  padding: 20px;
}
footer {
  text-align: center;
  padding: 10px;
  background: #f3f4f6;
}