change directory Wordpress stylesheet is in.
the theme style sheet is missing" problem, just write some theme info only in a file, named style.css and put in your theme directory.
add_filter('stylesheet_directory_uri','wpi_stylesheet_dir_uri',10,2);
/**
* wpi_stylesheet_dir_uri
* overwrite theme stylesheet directory uri
* filter stylesheet_directory_uri
* @see get_stylesheet_directory_uri()
*/
function wpi_stylesheet_dir_uri($stylesheet_dir_uri, $theme_name){
$subdir = '/css';
return $stylesheet_dir_uri.$subdir;
}