While working, ArchiCAD is a bit dark, so can you make it brighter?

[LeeJaeYoung]

RGB 223 192 134

[furtonb]

I think you just need to change the default background.

Click on an empty space in 3D view and check your 3D Styles:

There you can see your background settings, that default greyish colour is there in your screenshot:

I just link both colours and set them to white:

Do this for all 3D styles and you should be good.