Thank you so much for your info...
Unfortunately I use a S4: it is UNLOCKED, but it is i9502 (dual SIM), and there is ONLY one cooked ROM available (from SVA, ROM 5.5). Which is excellent by the way.
It has black background.
I am very happy about the ROM. I would not want to change to another cooked ROM. And even if I want, there it NO alternative English ROM to support dual SIM i9502 Samsung S4.
Is there a way that a NON-Tech-sawy like me can accomplish the change of background from black to white or clear? Yes, I cannot do programming, but I am able to fully implement rooting procedures and I know basic Unix commands and terminal operations..