In Logos 4 Mac, you cannot vary the THICKNESS of the line being used to underline text in a verse.
In Logos 4 Windows under the "Highlighting Menu" it allows you to create custom lines of varying thicknesses and also various colors.
This is extremely useful as a highlighting feature. It allows you to choose any thickness or any color of line to underline your text.
Logos 4 Mac desperately needs this same function, which is currently available only in Logos 4 Windows
Vote Here: https://logos.uservoice.com/forums/42823-logos-bible-software-7/filters/new