Mobile plugin issue

I want the width of the menu to be like in pc. It is all about the menu. All the website is beeing displayed correct except the central menu. So I believe I have to do smth with menu.

give me your url to check because I don't really understand

The url is www.inthessaloniki.com

ok, try to add this into one of your css file

If I add this in the code the width will be 1100px for pc when I want to be auto. I do not want in big resolution screens to has gaps on right and left.

I cannot understand why in mobile devices only changes. It is perfect in pc, laptop and with a widht on mobile device.

I don't understand, what you mean by "the same as on pc"
1/ the menu is responsive and its widht depends on the page width and the items becomes vertical (that is what happen and is the normal behavior)
or
2/ you give a width to force it and it will not be reponsive

now if this is not clear, give me correct information about your problem because by my side I don't see anything wrong