Linear gradient for marks over whole range

[Enlitened]

I am trying to create a slider that has a linear gradient that is applied to the whole range. i.e. the first and last few marks appear more transparent than the middle marks.

I have tried changing the z-index on the items rendered in renderTrack and renderMark but the marks always appear on of the track.

Something like this: background: 'linear-gradient(to right, transparent, white, transparent'

Is something like this achievable?