Taskbar's backgound icons not changing with theme color

[Forpli]

I am not sure if a solution similar to this one of @Aravisian can help with white icons on light taskbar

How to set the color of taskbar icons manually on zorin 15.3 lite?

The icons that look dark on the panel (taskbar) do so because they are the Symbolic icons. This can easily be changed by using the gtk.css file to specify to use the regular icons, instead of the symbolic ones. In ~/.config/gtk-3.0 directory create a new file and name it gtk.css. Paste the following into it and save the file once done. button, button.osd, button.text-button.toggle, button.image-button.toggle, button.destructive-action:disabled, button.destructive-action, button.suggested-act…

or this one

Setting QT5/6 apps to use GTK theme in Zorin OS

Updated to be accurate to current Zorin OS: In terminal, download the qt5 plugins and qt5ct configuration tool: sudo apt install qt5ct qt5-style-plugins Once installed, you will need to change some things in Root: sudo -i nautilus or thunar Or... nemo navigate to /etc/profile.d Open qt-style-override.sh and remove the line there, blanking the file. Save and close. next, open `qt-qpa-platformtheme.sh and change its contents to: export QT_QPA_PLATFORMTHEME=qt5ct Close out t…

When the icons are from flatpak-apps, they often don't respect system theme settings. You could then try this:

Flatpak Apps Look Out of Place? Here's How to Apply GTK Themes on Flatpak...