To color the text of your messages, Type Control-K (same time), a number (1-15), then your text.  (Note: there shouldn't be any spaces between the beginning and the end of the first word)
e.g. "4this is a test" will get you: 4this is a test
to color both the background AND the text, use the same process, but with 2 numbers separated by a comma.
e.g. "4,15red text with a gray background" will get you: 4,15red text with a gray background
0=white 1=black 2=2blue  3=3green  4=4red  5=5brown  6=6purple  7=7orange  8=8yellow  9=9bt.green  10=10cyan  11=11lt.blue  12=12bt.blue  13=13magenta  14=14gray  15=15lt.gray