How do I change the color of the AlertDialog message?

I have AlertDialog

and this message is displayed but the text color is white. It blends into the background. I tried to change the theme, but it doesn't work. How do I change the color of a message?

Relevant code:

AlertDialog.Builder builder;
builder = new AlertDialog.Builder(MainActivityGame.this);

builder.setTitle("Name");
builder.setMessage("Are you ");
builder.setCancelable(false);
builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
    @Override
    public void onClick(DialogInterface dialogInterface, int i) {
        //Submit default name, go home
        boolean isInserted = myDb.insertData(defaultName, triesTaken, difficultyText);
        if (isInserted) {
            Toast.makeText(MainActivityGame.this, "Your name was submitted", Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(MainActivityGame.this, "Error, your name wasn't submitted\n Have you entered a default name?\n Go to Settings/Default Name to set it up", Toast.LENGTH_SHORT).show();
        }
        Intent intent = new Intent(MainActivityGame.this, MainActivity.class);
        startActivity(intent);
    }
});
builder.setNegativeButton("No", new DialogInterface.OnClickListener() {
    @Override
    public void onClick(DialogInterface dialogInterface, int i) {
        userName.setVisibility(View.VISIBLE);
        submitName.setVisibility(View.VISIBLE);
        submitName.setEnabled(true);
        dialogInterface.dismiss();
    }
});
builder.create();
builder.show();