(Part of #5384 - MathML Core related CSS)

Mathematical rendering, like other text renderings can happen inline with prose or in the block direction and different elements employ different strategies for layout. According to common norms, these are treated a little differently. MathML Core proposes the introduction of two display types:

display: math and display: inline-math

These control box generation and layout according to their tag name, internally. It shoud be possible for authors to experiment/extend and provide custom layouts for when authors would like to override. The figure below illustrates differences in standard treatments of mathematical rendering depending on whether it is inline with text, or has a complete space in the block direction, as illustrated in the figure below.

These can be overridden and extended with custom layouts. display: contents computes to ``none`.