body {
  font-family: system-ui, sans-serif;
  max-width: 640px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
  color: #111;
  background: #fff;
}

nav {
  display: flex;
  gap: 1.5rem;
  padding-bottom: 1.5rem;
  margin-bottom: 1.5rem;
  border-bottom: 1px solid #ddd;
}

nav a {
  color: inherit;
  text-decoration: none;
}

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

nav a[aria-current="page"] {
  font-weight: 600;
}