It's a sad day when I have a scripting answer, of all people.
Go into Game_Temp, it's the very first thing in the script menu. At Line 1, hit enter, then type the following line:
Font.default_color = Color.new(255,255,255,255)
This has to be the first thing in the list, even before the line of green dashes. Also, since the scripts are in American English, it has to be spelled 'color', instead of the more European 'colour', so no U.
Now, that makes the font black. To get other colours- and I'm assuming that it goes RGB- just lower the first three sets of numbers; the first set is red, the second green, and the third blue. I think the fourth set is tone or intensity. Of coarse, like I said, that's assuming the order is RGB: so for red font, you would adjust it so that the numbers read, " 255,0,0,255", for yellow font its '0, 255, 255, 255', and so on.
You'll have to tinker with the numbers to get the colour you want.