Okular toolbar icons unreadable in Gnome with Adwaita Dark theme

I installed Okular on the default Gnome desktop to have a way to annotate my pdfs more powerful and streamlined than what Evince could offer.
I’m using the Adwaita Dark setting and the problem is with Okular’s toolbar icons: they are black on a dark background, so very hard to read.

Obviously, there is no setting in Okular itself to customize the Qt widgets appearance and I have no idea how to fire up a QT-theme editor.

I’ve installed Okular with flatpak and the KDE Adwaita adapter was included. This is the list of relevant flatpaks I got:

Fedora Platform                          org.fedoraproject.Platform
Freedesktop Platform                     org.freedesktop.Platform
default                                  org.freedesktop.Platform.GL.default
Freedesktop SDK                          org.freedesktop.Sdk
GNOME Application Platform version 3.38  org.gnome.Platform
GNOME Application Platform version 40    org.gnome.Platform
Adwaita dark GTK theme                   org.gtk.Gtk3theme.Adwaita-dark
Adwaita theme                            org.kde.KStyle.Adwaita
KDE Application Platform                 org.kde.Platform
QGnomePlatform                           org.kde.PlatformTheme.QGnomePlatform
QtSNI                                    org.kde.PlatformTheme.QtSNI
QGnomePlatform-decoration                org.kde.WaylandDecoration.QGnomePlatform-decoration
Okular                                   org.kde.okular

How can I either:

  • change the theme for Okular or Qt to a light one?
  • change the icons used by Okular to something readable on a dark background?

You can force fallback to the default Qt theme by uninstalling the Adwaida adapter:

flatpak uninstall org.kde.KStyle.Adwaita
flatpak uninstall org.kde.PlatformTheme.QGnomePlatform

I am also looking for themeing in qt flatpak apps but currently I don’t think it is possible.