W3C CSS2 Cascading Style Sheets, level 2 - instructional media + ...

Whether the first page of a document is :left or :right depends on the major
writing direction of the document and is outside the scope of this document.
However, to force a :left or :right first page, authors may insert a page break
before the first generated box (e.g., in HTML, specify this for the BODY element).
Properties specified in a :left (or :right) @page rule override those specified in
an @page rule that has no pseudo-class specified. Properties specified in a :first
@page rule override those specified in :left (or :right) @page rules.
Note. Adding declarations to the :left or :right pseudo-class does not influence
whether the document comes out of the printer double- or single-sided (which is
outside the scope of this specification).
Note. Future versions of CSS may include other page pseudo-classes.
13.2.5 Content outside the page box
When formatting content in the page model, some content may end up outside
the page box. For example, an element whose ’white-space’ property has the
value ’pre’ may generate a box that is wider than the page box. Also, when boxes
are positioned absolutely [p. 113] , they may end up in "inconvenient" locations.
For example, images may be placed on the edge of the page box or 100,000
inches below the page box.
A specification for the exact formatting of such elements lies outside the scope
of this document. However, we recommend that authors and user agents
observe the following general principles concerning content outside the page
box:
Content should be allowed slightly beyond the page box to allow pages to
"bleed".
User agents should avoid generating a large number of empty page boxes to
honor the positioning of elements (e.g., you don’t want to print 100 blank
pages). Note, however, that generating a small number of empty page boxes
may be necessary to honor the ’left’ and ’right’ values for ’page-break-before’
and ’page-break-after’.
Authors should not position elements in inconvenient locations just to avoid
rendering them. Instead:
To suppress box generation entirely, set the ’display’ property to ’none’.
To make a box invisible, use the ’visibility’ property.
User agents may handle boxes positioned outside the page box in several
ways, including discarding them or creating page boxes for them at the end
of the document.
13.3 Page breaks
The following sections explain page formatting in CSS2. Five properties indicate
where the user agent may or should break pages, and on what page (left or right)
the subsequent content should resume. Each page break ends layout in the
current page box [p. 176] and causes remaining pieces of the document tree
[p. 30] to be laid out in a new page box.
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