how to link child theme to child style-mobile.css

Sorry I wrote the file name wrong… should be theme-styles.php instead of style-mobile.php 🙂

OK,
I solved this issue…. alot of digging 🙂

bottom line, in the Includes dir there is a theme-styles.php file which use the following line to get the theme-styles.php file:

if($mantra_mobile==”Enable”) { wp_register_style( ‘mantra-mobile’, get_template_directory_uri() . ‘/style-mobile.css’ );}

using get_template_directory_uri() function override the theme-child.
in order to refer the theme-child should use get_stylesheet_directory_uri() function..

I add to my theme-child the theme-styles.php file with the right function

if($mantra_mobile==”Enable”) { wp_register_style( ‘mantra-mobile’, get_stylesheet_directory_uri() . ‘/style-mobile.css’ );}

now its work 🙂