In general it is not safe to convert any arbitrary floating-point value
to CSSPixels. CSSPixels has a resolution of 0.015625, which for small
values (e.g. scale factors between 0 and 1), can produce bad results
if converted to CSSPixels then scaled back up. In the worst case values
can underflow to zero and produce incorrect results.
Grid specification https://www.w3.org/TR/css-grid-2/#z-order defines
special painting order for grid items which should be the same as for
defined for inline-blocks in CSS2.