色Vector4

// 赤
SliderLife.gameObject.transform.FindChild("FillArea").GetComponentInChildren<Image>().color 
     = new Vector4(0, 0, 1, 1);
// 青
SliderLife.gameObject.transform.FindChild("FillArea").GetComponentInChildren<Image>().color 
     = new Vector4(1, 0, 0, 1);