The settings appear to be expecting Numix Frost (dark) not light because everything on the system is using Numix Frost by default except for the [b:idbuyrz8]Window Borders[/b:idbuyrz8] option has [b:idbuyrz8]Numix Frost Light[/b:idbuyrz8] set.
I switched it to Numix Frost instead and the system looks great. :)
PS. I would have submitted this as an issue on GitHub but it seems that this setup is not part of the GitHub repo.