Its probably to do with tifa and cloud being in a dark room, there are alot of times where she is in light, but they portray aerith in light probably because she is kinda like light and like a spirit?
Also, it may have something to do with clothing xD Pink doesnt go well with black xD
And tifa is said to be light by tetsuya in KH, but didnt say she was Cloud's light. :whistle: