you can also use decimal like
[c=#255,255,0]yellow to light blue[/c=#0,247,247]
btw you could also do this with the old MP! colouring and to put a background with them you use a commar after your text colour and then the colour of the background you want (colour of the text can be left blank).
EDIT: apparently plus doesn't handle decimal
EDIT2: I checked and MP! 3.xx could handle decimal, even Message Customizer! Live can handle people putting in decimal (though the RegExp isn't the best in places) so what can't MP!L handle it?