body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  color: #fff;
  background-color: #000;
}
header {
  background-color: #1a1a1a;
  padding: 1rem 0;
}
nav ul {
  list-style-type: none;
  display: flex;
  justify-content: center;
}
nav ul li {
  margin: 0 1rem;
}
nav ul li a {
  color: #fff;
  text-decoration: none;
}
main {
  padding: 2rem;
}
section {
  margin-bottom: 2rem;
}
footer {
  background-color: #1a1a1a;
  text-align: center;
  padding: 1rem 0;
}
@media (max-width: 600px) {
  nav ul {
    flex-direction: column;
  }
}