class attribute of the paragraph.
The text in parentheses says which edge of the container the paragraph
should be aligned against.
[narrow] (left)
[narrow border] (left)
[wide] (left)
[wide border] (left)
[narrow left] (right)
[narrow left border] (right)
[wide left] (spec: right; proposal: left)
[wide left border] (spec: right; proposal: left)
[narrow right] (left)
[narrow right border] (left)
[wide right] (left)
[wide right border] (left)
[narrow left right] (center)
[narrow left right border] (center)
[wide left right] (spec: center; proposal: left)
[wide left right border] (spec: center; proposal: left)