9.5.2 Controlling flow next to floats: the 'clear' property

Change
   # Clearance is introduced as spacing above the margin-top of an element.
   # It is used to push the element vertically (typically downward), past
   # the float.
to
   | Values other than 'none' potentially introduce clearance.
   | Clearance inhibits margin collapsing and acts as spacing above the
   | margin-top of an element. It is used to push the element vertically
   | past the float.
and shift to after value definitions.

Change
   # The clearance of the generated box is set to the amount necessary to
   # place the top border edge below the bottom outer edge of any
to
   | Requires that the top border edge of the box be below the bottom
   | outer edge of any
x3

Change
   # then its clearance must be set to the greater of:
to
   | then clearance is introduced and must be set to the greater of:

Change
   # The clearance can be negative.
to
   | The clearance can be negative or zero.

8.3.1 Collapsing margins

Change
   # An element that has had clearance applied to it never collapses
to
   | An element that has clearance never collapses

Change
   # When an element's own margins collapse, and that element has had
   # clearance applied to it
to
   | When an element's own margins collapse, and that element has clearance

Change last sentence of
   # Explanation: Without the 'clear', the first and last paragraphs'
   # margins would collapse and the last paragraph's top border edge
   # would be flush with the top of the floating paragraph. But the
   # 'clear' requires the top border edge to be below the float, i.e.,
   # 2em lower. That means that the margins must not collapse and
   # clearance must be added such that clearance + margin-top = 2em,
   # i.e., clearance = 2em - margin-top = 2em - 3em = -1em.
to
   | This means that clearance must be introduced.  Accordingly,
   | the margins no longer collapse and the amount of clearance
   | is set so that clearance + margin-top = 2em, i.e.,
   | clearance = 2em - margin-top = 2em - 3em = -1em.