Wordpress child theme css does not override parent css

I am using mies-child theme but the problem is that I cannot see the css changes affect my website.

Here's what my child style.css looks like:

/*
Theme Name: Mies Child
Theme URI: http://pixelgrade.com/demos/mies
Author: PixelGrade Team
Author URI: http://pixelgrade.com
Template: mies
Description: MIES is a front line parallax Architecture WordPress Theme prized for allowing you to present your activity within a delightful and captivating experience. It's perfect for a full range of presentations and portfolio projects of designers, architects or photographers.
License: Themeforest Split Licence
License URI: -
Text Domain: mies_txtd
Domain Path: /languages/
Tags: white, light, dark, responsive-layout, custom-colors, custom-header, custom-menu, featured-image-header, featured-images, full-width-template, theme-options, translation-ready
*/

This is my child functions.php file:

<?php
/*
 * ===== Theme Translation =====
 * Load the translations from the child theme if present
 */
add_action( 'before_wpgrade_core', 'mies_child_theme_setup' );
function mies_child_theme_setup() {
    load_child_theme_textdomain( 'mies_txtd', get_stylesheet_directory() . '/languages' );
}
/**

===== Loading Resources =====
Add all the extra static resources of the child theme - right now only the style.css file

*/

function mies_child_enqueue_styles() {

// Here we are adding the child style.css while still retaining all of the parents assets (style.css, JS files, etc)

wp_enqueue_style( ‘mies-child-style’,

get_stylesheet_directory_uri() . ‘/style.css’,

array(‘wpgrade-main-style’) //make sure the the child’s style.css comes after the parents so you can overwrite rules

);

}
add_action( ‘wp_enqueue_scripts’, ‘mies_child_enqueue_styles’ );

#javascript #php #css #wordpress