Category distinction

[dcarr]

Hello, I've searched and can't find this similar topic. I would like to be able to see a more distinct difference between the parent category and the child.  I do see the child is slightly indented, but I would like that to be more obvious.  What code would need to change and how?  or is there a better way.  I appreciate any guidance.  Either more of an indent or perhaps a different color for child?

Thank you