GTK4 ignores gtk-application-prefer-dark-theme, and did not follow the
portal's prefer-dark either, so Adwaita stayed light while the custom css
darkened only some surfaces - that is why pavucontrol had dark-grey labels
on dark backgrounds and a white content pane. GTK_THEME=Adwaita:dark fixes
GTK3 and GTK4 together.
Also recolour the stale ~/.themes Terminal-Dark leftovers, point gtk-4.0 at
a theme and icon set that exist, and start the particle layer from bspwmrc.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Cn3dHfbgNYdbZvzb1b3GQt
