Transform-
This is used to define whether an elements child elements are flattened or preserved in 3D space.
The options are:
(1) Flat, this is default and means that child elements are flattened.
(2) Preserve-3d, child elements keep their position in 3D space.
For maximum browser support, you should use the following prefixes:
(1) transform-style:
(2) -webkit-transform-style:
Transform-