I agree with SUPRFU, I didn’t know grid lines was editiable, I suggest adding it to your plugin anyways just so all the theme like settings are in the same place, it’d be easy to just make 1 trip and go.
Would it be a possibility to change the icons on the toolbars? The bright light blue doesn’t really fit the theme IMO, I’d download the icons re-color them darker just so they looked more in place