I just installed latest version 2.2.1 on Ubuntu Mate 20.04. I have dark mode enabled and right away I noticed issue after starting streamtuner2. If I select any radio station on left pane, right pane there is a column (2nd) names Station Title. This column has white background and very light gray text. It makes it very hard to read. How do you attach screen shot? Is there a work around this UI issue.

That's an artifact from the search function. The only way to adapt it right now would be changing uikit.py line 175:

row.setdefault("search_col", "#ffffff")

Unfortunately there's no fallback onto the default theme. In previous attempts it wasn't possible to use "transparent". Though we could have a config option for this. (More work than editing the file directly.)

One some Gtk versions you an just set it to an empty string.
That would only yield an occassional GtkWarning: Don't know color ''. It might be more bugprone for Gtk3 setups however.