function my_theme_enqueue_styles() {

    $deps = array( 'woocommerce-layout', 'woocommerce-smallscreen', 'woocommerce-general');

    wp_enqueue_style('header', get_template_directory_uri() . '/css/header.css', $deps, '3.2.6', 'all');

}

add_action( 'wp_enqueue_scripts', 'my_theme_enqueue_styles');