How to change the background colour on question?

When I click on an answer box the colour of the whole question turns egg yellow.

I cant seem to find anywhere where i can change this colour.

This color is the error highlight that appears by default for each required field. You can change this color from the form's Advanced Designer. Please check the screencast below.

Related Guide: Managing-Field-Error-States-and-Highlight-Effect#How-to-customize-the-highlight-effect