body {
  display: flex;
  flex-direction: column;
  font-family: Arial, sans-serif;
}

header {
  background-color: #004080;
  color: white;
  padding: 1rem;
  text-align: center;
}

nav ul {
  list-style: none;
  padding: 0;
}

nav ul li {
  display: inline;
  margin: 0 1rem;
}

nav ul li a {
  color: white;
  text-decoration: none;
}

aside {
  background-color: #f0f0f0;
  padding: 1rem;
  width: 200px;
}

aside ul {
  list-style: none;
  padding: 0;
}

aside ul li {
  margin: 1rem 0;
}

aside ul li a {
  text-decoration: none;
  color: #004080;
}

main {
  flex: 1;
  padding: 2rem;
  margin-left: 220px;
}

footer {
  background-color: #f0f0f0;
  padding: 1rem;
  text-align: center;
}

h1, h2, h3 {
  color: #004080;
}