I had missed out on adding this important meta tag...
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
That fixed it. Leaving the question up in case someone else does the same mistake.
Question
I created a simple website: http://mpl.mediatech.co.in using Foundation 5, and it works ok on Desktop / Firefox Responsive Design View:
but on the iphone / android phones, it looks like this:
What am I missing?
Solution
I had missed out on adding this important meta tag...
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
That fixed it. Leaving the question up in case someone else does the same mistake.