In drawing sheet tangent edges are appearing in grey in "Hidden lines removed" visual style but when switching to "Shaded with edges" mode all tangent edges are turning into black.
what I want is to change the tangent edge color in "shaded with Edges" Visual style.
Please see the attached PDF for any confusion.
Well, I am not sure how to specifically change tangent edges to another color. You can change ALL edges to another color though:
And then, when you are in a drawing, you can change the font of the edges:
You can even do this specifically in shaded with edges mode.
As for making the color of only tangent edges......not sure.
You might have to meticulously pick each one at the drawing level and change it manually.