message: Less non-sensical `.Section`s; Adds `.Narrow` for constraining layout widths without margins
diff: margin-right inherit !important
  .Section
  - @extend .Page
  - collapsed-margins(1em)
  + collapsed-margins(4em)
  +
  +.Narrow
  + max-width layout-narrow-width
  + margin-right auto
  + margin-left auto
  