Hello,
I don't know if it is the right place to say. Maybe it is better to directly submit an issue or raise a PR but as it is not yet released I prefer to do so.
On the latest master of dashboard on github, a semicolon is missing on line 4 :
:root { --nr-db-dark-text: #444; --nr-db-light-text: #eee --nr-db-disabled-text: #999; }
hence --nr-db-light-text and --nr-db-disabled-text are not defined.
Let me know if you want me to raise a PR or submit an issue.