[deletedpenguin]

If you download the git version, all the texture files are in an uncompressed format(jpgs, png, etc) rather than one .xbt file. Look around at the contents and you'll see how many images there are to change in order to get a decent white theme

If you just wanted to change the Orange color to something else, substantially less images to change. addons\skin.aeon.nox.5\themes\orange
There is only about a dozen images in there.

Thanks for the advice, I will have a go at making a white theme this weekend.

Keen to see how you go with this, if you're open to sharing?