Grid health bars

[Toeler]

Is there any way to change the 'background' of the health bars in grid? The bars of my frames are very dark and because the background is black I can't see if people have lost health very easily. I've tried changing the health bar colour to white and inverting the colours, which is really what I want...but that then inverts my mana bars colours, so as mana is used the bar fills up from the right in effect, which I don't like.