Defines the floating property. Floating elements create a new flow inside
an existing flow.
The properties left and top are equivalent, as as right and bottom.
All properties in the specification can be reduced to either left or
right in the computation phase.
Floating images cannot leave their containing block vertically or horizontally.
If negative margins are given, they may be shifted outside the content area,
but vertical margins will increase the 'empty-space' between the blocks instead
of messing up the previous element.