body { 
  background: #333333;
  color: #aaaaaa;
  font-family: sans-serif;
  padding: 30px;
}

a {
  color: #aaaaaa;
}

div#nav {
  text-align: center;
}

div#nav ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
}

div#nav li {
  display:inline;
}

div#nav li a {
 padding-left: 5px;
}

h3 a.ablack {
  font-size: xx-large;
}

li, ul.sublist {
  padding-top: 3px;
}

@media screen and (min-width: 768px) {
  .flex-container {
    display: flex;
  }

  .flex-container > div {
    margin: 10px;
    padding: 10px;
    width: 50%;
    border-style: solid;
    border-width: 1px;
    border-color: #aaaaaa;
  }
}