body {
  font-family: Arial, sans-serif;
  background: #f4f4f4;
  margin: 0;
  padding: 0;
  line-height: 1.6;
}
header, footer {
  background: #004b6b;
  color: white;
  text-align: center;
  padding: 1rem;
}
nav {
  background: #0077a3;
  padding: 0.5rem;
  text-align: center;
}
nav a {
  color: white;
  margin: 0 1rem;
  text-decoration: none;
  font-weight: bold;
}
main {
  max-width: 1000px;
  margin: auto;
  background: white;
  padding: 1rem;
  border-radius: 8px;
  box-shadow: 0 0 10px rgba(0,0,0,0.1);
}