header {
  background: #333;
  color: white;
  width: 100%;
  padding: 1em;
  text-align: center;
}

header h1 {
  margin: 0;
  font-size: 1.5em;
}

header h1 a {
  color: white;
  text-decoration: none;
}

nav {
  margin-top: 0.5em;
}

nav a {
  color: white;
  margin: 0 1em;
  text-decoration: none;
}

nav a:hover {
  text-decoration: underline;
}

nav a.active {
  font-weight: bold;
  text-decoration: underline;
  color: yellow;
}