Responsive friendly needed

I’m building responsive sites for client that are in need of easy to use password screen on mobile devices. I’d like to be able to set the viewport to something like:
<meta name=”viewport” content=”width=device-width; initial-scale=1; maximum-scale=1″ />

And to be able to have the login screen be full width of the device.

http://ww.wp.xz.cn/extend/plugins/password-protect-wordpress/