* {
  box-sizing: border-box;
}

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

header {
  background: #2c3e50;
  color: #fff;
  padding: 1.5rem 1rem;
  text-align: center;
}

header h1 {
  margin: 0 0 0.25rem;
}

nav {
  background: #34495e;
}

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

nav a {
  display: block;
  padding: 0.75rem 1.25rem;
  color: #ecf0f1;
  text-decoration: none;
}

nav a:hover,
nav a.active {
  background: #1abc9c;
}

main {
  max-width: 700px;
  margin: 2rem auto;
  padding: 0 1rem;
  text-align: center;
}

footer {
  text-align: center;
  padding: 1rem;
  color: #777;
  font-size: 0.9rem;
}