Shoutbox

argb = alpha, rgb

If you set the alpha to 0 you get complete transparency, if you set it to the highest(of which i can't remember the exact number) it will be completely opaque(not transparent)

therefore you need:

code:

---

Background:argb(0,255,255,255);

---

EDIT: What you did was change one of the colour values, which of course would of changed the colour, not the alpha.