Responsive website zoomed out to full width on mobile

as suggested here http://webdesign.tutsplus.com/tutorials/htmlcss-tutorials/quick-tip-dont-forget-the-viewport-meta-tag/

<meta name="viewport" content="initial-scale=1">

would be an even better choice as it makes going from portrait to landscape and back a much more pleasant user experience as with/height would adopt naturally because of the possible auto-scaling.

Add this to your HTML head..

<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1">

This tells smaller device browsers how to scale the page. You can read more about this here: https://developer.apple.com/library/content/documentation/AppleApplications/Reference/SafariWebContent/UsingtheViewport/UsingtheViewport.html