Marked played indication is broken with HighContrast themes.

Steps to reproduce

1. Set the gtk theme to a HighContrast variant
2. Open the app
3. Mark some episodes as played

Reproducible in:

• Flatpak unstable: yes
• Other: ~0.2.0 to 0.4.4 I think

Current behavior

With Adwaita, we use the dim-label style-class for Episode titles, to indicate that they have been played. HighContrast however does not really care about dim-label. Further more, having the only indication being visual poses extra accessibility problems.

Adwaita:

High Contrast:

Expected behavior

Episodes can be distinguished as played by everyone.