*
  @include box-sizing(border-box)

body
  margin: 0

main
  font: 1em "Helvetica Neue", sans-serif
  margin: 0 auto

*, *:before, *:after
  @include box-sizing(border-box)

body
  margin: 0

main
  font: 1em "Helvetica Neue", sans-serif
  margin: 0 auto

Cover :before and :after with box sizing.
Cover :before and :after with box sizing.
