cannot make very nice shading with low-resolution 2-colour or 8-colour
You don't need shading or much extra space just a 1 pixel border with top & left pale and right and bottom dark. The windows 3.1 3D enhancement was fine on 16 colour EGA. Though some CGA displays might only have done 8 shades of the 16 colour CGA text mode. CGA graphics was only 4 colours or black and white (2 bit or 1 bit). Windows 1 to 3.1 only used the 1bit mono mode of CGA.
The next lowest depth wasn't 8, but black and white Hercules and CGA monochrome modes. Then the paler lines were dotted. However CGA and Hercules Windows was a curiosity, The minimum practical windows was 640 x 350 16 colour EGA.
Biting the hand that feeds IT
