.postpage {
  box-sizing: border-box;
  width: 100%;
  max-width: 50em;
  padding: 3em 5%;
  align-self: center;
}

.postpage {
  box-sizing: border-box;
  width: 100%;
  max-width: 60em;
  padding: 3em 5%;
  align-self: center;
}

Increase max width of .postpage
Increase max width of .postpage [skip ci]
