The word “black” there tells it to use that color for the class red-text. Obviously that is wrong. We could just change it to the word “red”. But you can also refer to colors by a code number. For example, from the description:
Red #FF0000
So, you can just use the number code instead of the words “black” or “red” to get the color red. Try substituting “#FF0000” for the word “black” and see what happens. Do that for the others.