This property describes how block-level content of a block is aligned vertically. Values have the following meanings:
Note. Justify is another possible value. It is hard to implement though, especially in presence of floats
Note: should 'start' | 'end' values be included also?
Elements with 'block-vertical-align' value other than 'auto' establish a new block formatting context. Content of such block is formatted as follows:
When this property is applied to a table cell (or any other element supporting vertical-align in this version of CSS, e.g. table-cell), this property takes priority over 'vertical-align'.
In paged media and in multi-column layout, page breaks are calculated first, then the content is vertically aligned according to the property within each portion of the parent block.
Issue: What is the set of values applicable to vertical layout? Should block-align and block-vertical-align be physical and switch their meaning in vertical? Or should they be logical?