html {
  box-sizing: border-box; }

*,
*::after,
*::before {
  box-sizing: inherit; }

#page-wrapper {
  max-width: 68em;
  margin-left: auto;
  margin-right: auto;
  background: yellow; }
  #page-wrapper::after {
    clear: both;
    content: "";
    display: table; }