custom-viewport.php

<?php
/**-------------------------------------------
* @package Code Snippets
* @link http://rhythmshahriar.com/code/
* @author Rhythm <[email protected]>
* @copyright Copyright (c) 2013, Rhythm Shahriar
-------------------------------------------------*/
//* Add custom Viewport meta tag for mobile browsers
add_action( 'genesis_meta', 'rs_viewport_meta_tag' );
function rs_viewport_meta_tag() {
echo '<meta name="viewport" content="width=device-width, initial-scale=1.0"/>';
}

viewport.php

<?php
/**-------------------------------------------
* @package Code Snippets
* @link http://rhythmshahriar.com/code/
* @author Rhythm <[email protected]>
* @copyright Copyright (c) 2013, Rhythm Shahriar
-------------------------------------------------*/

//* Add Viewport meta tag for mobile browsers (requires HTML5 theme support)
add_theme_support( 'genesis-responsive-viewport' );