body {
  background: #f4f4f4;
  font-family: Arial, Helvetica, sans-serif;
  line-height: 1.5;
  margin: 0;
}

header {
  background: #333;
  color: #fff;
  text-align: center;
  padding: 0.5rem;
}

main {
  padding: 2rem;
}

nav {
  background: #444;
  padding: 0.2rem 2rem;
}

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

nav a {
  padding: 10px;
  color: #fff;
  text-decoration: none;
}

nav .current > a {
  color: yellow;
}

.message--error {
  color: red;
}

.message--success {
  color: green;
}

.message--warning {
  color: orange;
}