body {
  font-family: system-ui, sans-serif;
  margin: 0;
  padding: 0;
  background: #fdfdfd;
  color: #222;
}

header {
  background: #003366;
  color: white;
  padding: 1em;
}

nav ul {
  display: flex;
  justify-content: space-between;
  list-style: none;
  padding: 0;
  margin: 0;
}

nav a, nav select {
  color: white;
  background: transparent;
  border: none;
  font-size: 1em;
  margin: 0 1em;
  cursor: pointer;
}

main {
  padding: 2em;
  max-width: 800px;
  margin: auto;
}

.kernpunten {
  list-style: none;
  padding: 0;
}

.kernpunten li {
  margin: 0.5em 0;
}

.button {
  display: inline-block;
  margin: 1em 1em 0 0;
  padding: 0.5em 1em;
  background: #003366;
  color: white;
  text-decoration: none;
  border-radius: 4px;
}

footer {
  text-align: center;
  padding: 1em;
  background: #eee;
  margin-top: 2em;
}