Bar / line graphs render invisibly

[afontenot]

As illustrated in the screenshot below, every line and bar chart appears to be rendering with a transparent color. I can tell that it is rendering, at least in the case of the octave spectrum graph, because if you look very closely you can see that the text appears (in white!) above each octave bar.

This is probably some theme related issue? I'm using the AppImage of the latest release.

System Information:

• Operating System: Arch Linux x86_64
• KDE Plasma Version: 5.92.0
• Kernel Version: 6.6.10-arch1-1 (64-bit)
• Graphics Platform: Wayland
• Gtk versions: 2.24.33, 3.24.39, 4.12.4

[afontenot]

This is a duplicate of #249