.primary-margins {
  margin-left: calc(min(50%, max(0px, 100% - 900px)) / 2);
  margin-right: calc(min(50%, max(0px, 100% - 900px)) / 2);
}

.boxed {
  padding: 10px;
  margin-top: 10px;
  margin-bottom: 10px;
  background-color: lightgray;
}

.no-bottom-margins {
  margin-bottom: 0;
}

.no-top-margins {
  margin-top: 0;
}

body {
  background-color: darkslategray;
}

address {
  background-color: ivory;
  text-align: center;
  font-style: normal;
}

footer {
  text-align: center;
}