body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  line-height: 1.6;
}

header, footer {
  text-align: center;
  padding: 20px;
  background: #f4f4f4;
}

nav ul {
  list-style: none;
  background: #333;
  padding: 0;
  margin: 0;
  display: flex;
  justify-content: center;
}

nav ul li {
  margin: 0;
}

nav ul li a {
  display: block;
  padding: 14px 20px;
  color: white;
  text-decoration: none;
}

nav ul li a:hover {
  background: #555;
}

main {
  padding: 20px;
  max-width: 900px;
  margin: auto;
}

section {
  margin-bottom: 30px;
}

h2 {
  color: #333;
}

footer {
  margin-top: 40px;
}