Is there a way to change text color other than the options given?

I want to use Purple on March 26 in honor of "Epilepsy Awareness Day"

Many people I know are dying their hair purple or getting a tatoo.

Another friend is trying to rays 100 pounds to donation (I was only able to give 20 on a fixed income).

Just my way to support the cause.

At the top of the message box, there is the font colour button you can press. If you don't like the colour options given, you can choose your own by entering the colour hex no in the popup.