slideout sidebar in mobile

hello my website is https://sekizyirmibes.com/ if you take a look.

my problem is: in mobile phone the sidebar is hidden. there is a toggle button for see the sidebar. i realy like that. but its not happen all the time. i mean its not workin all phone. the sidebar shown the bottom of site in some phone, there is no toggle and slideout sidebar. i want to toggle button in all phone. i think that kind of resolution problem. because there is a file which name is responsive.css, the file include some resolution value about mobile phone. i tried changing them but i didnt make it. so whats your suppose?