The css file you pointed out had a lot of commented areas, so I have deleted them and updated the file.
The sizes should go from top to bottom as you said.
I take your point about resolution and viewport, which is one reason i added the js grid overlay to the home page.
The thing is, when the viewport is 768 wide or less, the floating toolbar moves from the side of the screen to the top.
There is no point before this that the navigation starts to wrap
as you can see from the screenshot, the navigation is wrapping on the tablet whilst the viewport is > 768, with the toolbar still parked on the right hand side