body {
  font-family: Arial, sans-serif;
  margin: 0; padding: 0;
  background: #f4f7f9;
  color: #333;
}
header {
  background: #2c3e50;
  color: white;
  padding: 2em;
  text-align: center;
}
nav {
  background: #34495e;
  padding: 1em;
  text-align: center;
}
nav a {
  color: white;
  margin: 0 1em;
  text-decoration: none;
}
main {
  max-width: 900px;
  margin: auto;
  padding: 2em;
  background: white;
}
section {
  margin-bottom: 2em;
}
footer {
  background: #2c3e50;
  color: white;
  text-align: center;
  padding: 1em;
  font-size: 0.9em;
}