Hate to be that guy, but the dollar should be red.

Totally valid feedback, though this is a known issue with our syntax grammar: https://github.com/PowerShell/EditorSyntax/issues/23. Once the grammar is fixed the theme should work correctly!
Keeping this bug open for now because I imagine other people will come here to report the same issue :)
Closing this as it is an editor syntax issue tracked PowerShell/EditorSyntax#23
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Keeping this bug open for now because I imagine other people will come here to report the same issue :)