Understanding neumorphic design shadows can be tricky, but I hope this pen can make sense.
A neumorphic element usually consists of two shadows, a lighter shadow and a darker shadow.
Imagine there's a light shining on your element, it would make sense for the lighter shadow to be nearer to the light and the darker shadow to be furthest away from the light. Simple.
This only works effectively if your element's background color is the same as the background it sits on.
For elements that need to look like they dip, I.e. they've been pressed, just set the box-shadow to
inset
and reverse the shadows, darker nearer the light source and lighter further away.
Hope this helps and have fun toggling the shadows below