UI improvement: Selected line border color vs. Currently-Playing bg-color

[porg]

Status quo

The border color of the selection frame (= selected line) is the same as the bg-color of the currently playing line. Hard to quickly realize what's playing and what's selected, especially when currently-playing and currently-selected are adjacent or the same.

Proposed change

The border color is the theme color with the brightness/saturation slightly increased. This will help to differentiate them visually.