Sticky not working anymore with my new template

Hello,

I am currently working on changing my template (the new one is a FavThemes one), and in this new one, I can't get the sticky menu to work.
Here is one page where you can see it :
30nov2018.rouchenergies.fr/chauffage/pom...chaleur-air-eau.html

I have to tell you I already had to manage to move my logo outside the nav position, because if I don't, the sticky menu covers the logo!
But since I did that, the sticky menu is not sticky anymore...
Once I've said that, I also have to tell you I tried to unpublish the logo module, and it doesn't change anything: the menu does not stick to the top of the screen...

I can see under the Advanced params of the module, a field called :
Container sticky
the tooltip says : Writing class at center for the site (container).
Maybe it's because english is not my mother tongue, but II don't understand what to do with this??

PS: in the description of JUXmegamenu, you say that there are 6 different themes. That's wrong: there are only 3 (dark blue, black and white, and red) : would something be missing in my installation?

Hello,
I just sent you a login.
I love JUXmegamenu, so I hope you will get it working
Thanks

Hi!
Thank you for your help, but it still does not work on mobile.
On large screen it is now perfect, thanks to you, but as soon as you shrink the size of the screen the sticky thing don't work anymore.
This is true for both narrow screens and mobile screens. Have a look please.
I hope so much you can find a solution because I really do love your extension.
You still have backend access.
Thanks.

Hello,
It is a little better, but I'm afraid it is still not working normally.

Let me show you.

Here is what I get on this new template:

Mobile menu, closed :

Mobile menu, open :

While this is what I should get (this what I actually get on my previous template) :

Mobile menu, closed :

Mobile menu, open :

I guess something is going wrong with nav position?

Do you think you can fix it or do you think I should get another template?

Thank you.

Hi,
It seems to be working fine Thank you!
Is there anyway for me to know what you've done, in order not to ask your help again if ever there is a template upgrade or so?
Thanks again.

Flo