style.php

<?php
/**
 * Add minified and RTL Stlysheets with automatic theme version
 * Load styles for specific stylesheets
 */
function theme_name_css() {

	$template_directory_uri = get_template_directory_uri();
	$rtl                    = ( is_rtl() ) ? '-rtl' : '';
	$suffix                 = ( defined( 'SCRIPT_DEBUG' ) && SCRIPT_DEBUG ) ? '' : '.min';
	$theme_name             = wp_get_theme( 'theme-name' );

	// Depending on the settings RTL or minified version will be loaded
	wp_enqueue_style( 'theme-name-style', $template_directory_uri . '/css/style' . $rtl . $suffix . '.css', false, $theme_name['Version'] );

	if ( is_child_theme() ) {
		$theme = wp_get_theme();
		wp_enqueue_style( 'theme-name-child-style', get_stylesheet_uri(), false, $theme['Version'] );
	}

	$page_id     = get_queried_object_id();
	$post_type   = get_post_type( $page_id ):
	if ( ! empty( $post_type ) ) {
		wp_enqueue_style( 'theme-name-' . $post_type , $template_directory_uri . '/css/style' . $post_type . $rtl . $suffix . '.css', false, $theme_name['Version'] );
	}

}
add_action( 'wp_enqueue_scripts', 'responsive_css' );