if you made a gtk theme and adapt a color pallette. its in ~/.local/share/lxqt/palettes/
this is mine gruvbox !
[Palette]
base_color=#282828
highlight_color=#076678
highlighted_text_color=#ffffff
link_color=#0000ff
link_visited_color=#ff00ff
text_color=#d8c8a2
window_color=#282828
window_text_color=#d8d6d0
gtk theme is :
/home/ringo ->pacman -Qs gruvbox
local/gruvbox-material-gtk-theme-git r14.cc255d43-1
Gruvbox Material theme for GTK, Gnome, Cinnamon, XFCE, Unity and Plank
local/gruvbox-material-icon-theme-git r14.cc255d43-1
Gruvbox Material icon theme
/home/ringo →