The matrix() CSS function specifies a homogeneous 2D transformation matrix comprised of the specified six values. The constant values of such matrices are implied and not passed as parameters; the other parameters are described in the column-major order.
The perspective() CSS function defines the distance between the z=0 plane and the user in order to give to the 3D-positioned element some perspective. Each 3D element with z>0 becomes larger; each 3D-element with z<0 becomes smaller. The strength of the effect is determined by the value of this property.
The rotateX()CSS function defines a transformation that moves the element around the abscissa without deforming it. The amount of movement is defined by the specified angle; if positive, the movement will be clockwise, if negative, it will be counter-clockwise.
The <transform-function> CSS data type denotes a function applied to an element's representation in order to modify it. Usually such transform may be expressed by matrices and the resulting images can be determined using matrix multiplication on each point.