I am trying to make a very simple diagram. I have these arrow-like objects that are inside of a transparent box. The arrows have this "shadow" on them, making them look dark. This effect looks fine on everything but the yellow arrows. I have removed all shadow effects, messed with lighting a little, and nothing changes. I am thinking it is texture related. I brought one arrow outside of the box, and it is still there. I have included a couple screenshots of the image and my settings.
I am extremely new to blender, and I am trying to keep this project relatively simple, so I would appreciate the simplest possible fix.