change color of pop up box

I am not sure if I have understood your question correctly.

I would suggest you to please explain your question a bit more in detail and we will try to help you. 

We will wait for your response.

Hi, sorry I didn't realise that posted. I found my answer.

I wanted to change the offwhite error pop up box that comes up if someone misses a required field. The light colour meant they couldn't then read the question in white text as I use  black background.

My solution was found under 'advanced designer' - 'color scheme' - 'simulate error state' - change background color to black.

:-)