Hi Dyan,

Thanks for your post.

If I am not wrong, you are trying to change the background color of harness appearing in the UI screen or active foreground or work area.

I have researched about it and found it can be done under the "Base settings" tab of the skin rule of your application.

Kindly select "Specify styles" under "Background" heading in Base settings tab. You can configure your background in different types as "Solid", "Gradient", "Image" or "None" with desired background color mentioning color code or selecting the colors from color picker box.

You can also add attribute directly to a attribute by adding a configuration under "Additional styles" with a desired value.

Kindly refer to attach screen-shot for better clarity. 

Please do notify me,if this information helps you.

If the image isn't clear, please refer to attached file.

Thanks,

Asif