To change the survey colours first select the style area in which you wish to do it. Options include Desktop, Tablet (horizontal+vertical) and Mobile (horizontal+vertical). In this example the style area is Desktop, but the settings are identical in all the style areas.
Click the Colors menu on the left to adjust the settings:
You can edit for example following Color sections:
Single choice & Multiple choice:
Tips & Tricks!
You can put RGB or hex values to the color picker. Just erase the current value and write e.g. rgb 255 255 255 and press enter to set the color.