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

.nav-menu {
  background-color: #f2f2f2;
  padding: 10px;
  text-align: center;
}

.nav-menu a:hover {
  background-color: #333;
  color: #fff;
}

main {
  padding: 20px;
}