Change child theme

I try to use child theme for “Llorix One Lite” theme.I do it step by step using below wordpress ducument.

https://codex.www.ads-software.com/Child_Themes

Nothing works good. there are some problem that t couldn’t fixed it.

1- My website is rtl, as it mention on wordpress documentation I put:

/*
Theme Name: llorix-one-lite-child
Template: llorix-one-lite
*/

to rtl.css of child theme and also put:

if ( is_rtl() ) {
  wp_enqueue_style(  'style-rtl',  plugins_url('/rtl.css', TRUE) );
  wp_enqueue_script( 'script-rtl', plugins_url('/js/script-rtl.js',  TRUE) );
}

to function.php of child theme.

2- I can’t change anythings on style.css of child theme and it seams in everything loaded from parent theme css file. for example I put:

.sticky-navigation .main-navigation a {
	color: 	#ffffff;
}

on child theme style.css to change the navigaition menu bar but it didn’t work.

Alse I change function.php of child theme as below:

<?php
add_action( 'wp_enqueue_scripts', 'theme_enqueue_styles' );
function theme_enqueue_styles() {
    //wp_enqueue_style( 'parent-style', get_template_directory_uri() . '/style.css' );
    wp_enqueue_style( 'rtl-style', get_template_directory_uri() . '/rtl.css' );

	wp_enqueue_style( 'admin-style', get_template_directory_uri() . '/css/admin-style.css' );
	wp_enqueue_style( 'bootstrap.min-style', get_template_directory_uri() . '/css/bootstrap.min.css' );
	wp_enqueue_style( 'font-awesome-style', get_template_directory_uri() . '/css/font-awesome.css' );
	wp_enqueue_style( 'font-awesome.min-style', get_template_directory_uri() . '/css/font-awesome.min.css' );
	wp_enqueue_style( 'ielt9.css-style', get_template_directory_uri() . '/css/ielt9.css' );
	wp_enqueue_style( 'welcome-style', get_template_directory_uri() . '/inc/admin/welcome-screen/css/welcome.css' );
    wp_enqueue_style( 'welcome_customizer-style', get_template_directory_uri() . '/inc/admin/welcome-screen/css/welcome_customizer.css' );

}

if ( is_rtl() ) {
  wp_enqueue_style(  'style-rtl',  plugins_url('/rtl.css', TRUE) );
  wp_enqueue_script( 'script-rtl', plugins_url('/js/script-rtl.js',  TRUE) );
}
?>

And style.css as below:

/*
 Theme Name:   llorix-one-lite-child
 Theme URI:    https://www.tarkcigar.com/wp-content/themes/llorix-one-lite-child
 Description:  llorix one lite Child Theme
 Author:       Mohammadreza Fathi
 Author URI:   https://tarkcigar.com
 Template:     llorix-one-lite
 Version:      1.0.0
 License:      GNU General Public License v2 or later
 License URI:  https://www.gnu.org/licenses/gpl-2.0.html
 Tags:         light, dark, two-columns, right-sidebar, responsive-layout, accessibility-ready
 Text Domain:  llorix-one-lite-child
*/

.sticky-navigation .main-navigation a {
		color: #313131;
}