.container {
  max-width: 1200px;
  margin: 0 auto;
}

nav {
  text-align: center;
}

nav ul {
  display: inline-block;
  list-style-type: none;
  padding: 0;
  margin: 0;
}

nav li {
  display: inline-block;
  margin: 0 10px;
}

nav a {
  display: inline-block;
  padding: 15px 25px;
  color: #fff;
  background-color: #333;
  text-decoration: none;
  font-size: 24px;
  margin: 10px;
}

main {
  display: inline-block;
  vertical-align: top;
  width: 50%;
}

header, footer {
  clear: both;
  text-align: center;
}

h1 {
  font-size: 36px;
}

.description {
  font-size: 24px;
  line-height: 1.5;
  margin-bottom: 20px;
}

nav {
  width: 100%;
}

nav ul {
  text-align: center;
}

nav li {
  display: inline-block;
  margin: 0;
}