message: Includes a class for a constrained page width + narrow variant; in addition to the standard page
diff: height 100%
  overflow hidden
  +.Constrain
  + for i in (1..8)
  + @media (min-width: (block_width_mar * i) + unit)
  + center(block_width_mar * i)
  +
  + @media (max-width: (block_width_mar * 3) + unit)
  + center(90%)
  +
  + &--narrow
  + max-width (block_width_mar * 2)
  +
  .Page
  + @extends .Constrain
  margin topbar_h auto
  - padding unit
  + padding 1em 0
  .Container
  width 100%
  &__content
  flex 1
  -
  -for i in (1..8)
  - @media (min-width: (block_width_mar * i) + unit)
  - .Page
  - center(block_width_mar * i)
  -
  -@media (max-width: (block_width_mar * 3) + unit)
  - .Page
  - center(90%)
  