RTL flipping does not handle transform, linear-gradient properties

[Alex Bertram]

When flipping CSS from LTR to RTL, the transform property also needs to be mirrored, mostly by reversing the sign of translations and rotations:

transform: translateX(35px);

should become:

transform: translateX(-35px);

And

 background-image: linear-gradient(45deg, #00CF79 0%, #00cfcd 100%);

should become:

 background-image: linear-gradient(-45deg, #00CF79 0%, #00cfcd 100%);

Is there perhaps a fix for this upstream, or would you be open to a PR?