Property Reference - CSS Reference - page 261

Name
transform-style
Values:
flat | preserve-3d
Initial value:
flat
Applies to:
Block- and inline-level elements
Inherited:
No
Computed value:
Same as declared value
Description:
Defines whether an element transformed in simulated 3D space should have its children
rendered using a flat style, thus putting them all in the same 2D plane as the element, or at-
tempt to use a 3D effect where children with positive or negative z-index values may be
rendered “in front of” or “behind” the element's plane as it rotates. Elements whose overflow
value is hidden cannot preserve 3D effects and are treated as though the value of transform-
style is flat .
Examples:
li {transform-style: preserve-3d;}