Change responsive menu activation

Currently there is no options available in Theme Options for this feature. If you want to customize it then you need to make a child theme and modify accordingly.

function bpchild_remove_scripts() {
    // Dequeue JS of parent theme
    wp_dequeue_script( 'blue-planet-theme-script-custom' );
    // Now add you own JS file
    wp_enqueue_script('bpchild-theme-script-custom',get_stylesheet_directory_uri().'/js/custom.js', array('jquery'),'1.0', TRUE);
}
add_action( 'wp_enqueue_scripts', 'bpchild_remove_scripts', 20 );

Now in the script file, copy content from parent theme and paste it in our file.

jQuery(document).ready(function($){
    jQuery('nav#site-navigation').meanmenu({
      meanScreenWidth: "640"
    });
});

To change the trigger point of mobile menu, change number in place of “640”. Default value is 640. Number represents the screen size in pixel.

Hope you got what you needed.