body {
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.5;
  margin: 0;
  padding: 0;
}

header {
  background-color: #2c3e50;
  color: white;
  padding: 20px;
}

h1 {
  margin: 0;
}

main {
  margin: 20px;
}

ul {
  list-style: none;
  padding: 0;
}

li {
  margin-bottom: 10px;
}

a {
  color: #3498db;
  text-decoration: none;
}

@media screen and (max-width: 768px) {
  main {
    margin: 10px;
  }
}