Is it ok to use differently navigation on mobile & desktop device, if there are 3 main categories that users are using?
This is website for the food, and I think bottom navigation with the main actions are the best position and the layout is clear and readable.
Is bottom navigation really such a bad practice for the mobile sites?
The answer is yes, bottom navigation is okay, and given that you only have three main categories, you can definitely make this work. However, it requires a relatively new approach and you won't see this listed as a "best practice" because it hasn't yet had time to become seasoned (as of Feb 2017). Apple and a few other UX pioneers have tried this "bottom nav" / "action drawer" approach. The bottom nav has three accessible call-to-actions and can also be swiped up for more functionality if needed. Hope this helps
An important thing needs to be added.
Even though this kind of navigation is very handy, you need to consider mobile browsers that display their own navigation at the bottom (e.g. stock "Internet" Samsung browser). If you add a navigation fixed to the bottom than on scrolling down, it will be covered by that browser's own nav bar.
I myself am at the point of trying to find a solution for that but no luck so far.
A loosely related case: tool menus in the Photoscape image editor are placed at the bottom of the working area:
For some reason I find this placement extremely convenient, especially, compared to the common top placement of tool menus (e.g. MS Office Ribbon menu layout). I cannot explain why I feel it this way, but my feeling of greater comfort has remained consistent over years of use of the Photoscape editor.
I could speculate that it has something to do with requiring less eye and mouse movements between the object of work and the menus, even though I cannot formulate exactly what. Just a hint to start you thinking in that direction.
