Allow bars to change colors based on certain values/percentages

I'd like to be able to represent when a player is bloodied, dying, and dead automatically during D&D games. It would be nice to be able to add/change colors for each bar based on certain values/percentages that I can set manually, to keep it system agnostic. Example: >50% - Green 0 - Yellow <= 0 - Red <= -50% - "X" out the token/Dead "pose" It would also be nice if I'm planning on reusing scenes to allow NPC's to just go invisible (or change image to a dead version) when HP is <= 0 or when I check a box off their settings.

awesome idea. As an edit, instead of "green" or "yellow", have something with "color numbers" so you can have whatever color you'd like (similar to auras)