You are only modifying GTK themes, QT themes are a bit of confusing. Easiest way to get a QT dark theme is to install kvantum (sudo apt install qt5-style-kvantum) and chose a dark theme there. Let us now how it work.
Thank you! I did it and it works fine. Now, it seems (I have not tried each and all) al LXQt apps respect my theme.
Kvantum is simply great. It’s interface is not obvious because definitely not mainstream, but it ‘‘just makes sense’’: there are 4 main sections, which unfold when clicked on, mirroring 4 usage stages: install themes, change them, configure, configure per app(s). the only faulty points:
- Terrible, probably most mechanical, translations (had to switch to english to understand a bit ;-)).
- Not a word about where/how to get other themes, while the feature is implemented (one can define a custom theme folder), probably related to below:
- Help unavailable (nothing happens when clicking the button), even in english.
EDIT: Help seems to have the form of a “what’s this” pointer that should act when placed on an interface element that has help. But it only shows a tooltip that we already have by default anyway.
For the record, I found a great dark theme among the ones that come with Kvantum: KvDarkRed (modified).
I forgot, after choosing the theme in kvantum, you will need to change the “Qt-style” for the kvantum one.
So, I had to find haw to activate the chosen Kvantum them as well: LXQt setting => appearance => widget style “kvantum” or “kvantum-dark” (no difference by me). PS: see also last paragraph below.
I would argue that there is far too much confusion about styling/theming. However, most linux distribs are equally confusing. In particular, here in Lubuntu, it is totally counter-intuitive that setting a theme in LXQt setting => appearance => “LXQT theme” does ‘’’’‘not’’’’’ set a theme for Qt apps, firstly the ones of LXQt itself, isn’t it? (Orally, I would say: what the f*ck!!!)
Most if not all also are based on an underlying software windowing framework which has its own styling/theming configuration that come with its own styling/theming config, that the desktop environment transfers as is to users. Instead of integrating it into meaningful, coherent whole… After all, there is only visual theme/style ultimately . With Lubuntu we thus have the whole --BlackBox-- OpenBox config, that mostly covers the same points as the LXQt one. By the way, I also set “KvDarkRed” as theme in the OpenBox config, don’t know if I had to do it… Precisely the confusion I am talking about.
PS: The interface for posting on this forum is pretty annoying with its tiny edit and preview windows. I am also a little surprise the spellchecker underlines “english” .