Correct Way to style print

Hi, I want to style the print result. I have copied the template to child theme folder. However, only product list padding is changed when editing styles.css. Any other modifications (line spacing, other paddings, margins) have to be written on functions.php of child theme like this instruction below.

function example_price_free_delivery_note() {
    ?>
        <style>
            .delivery-note .head-item-price,
            .delivery-note .head-price, 
            .delivery-note .product-item-price,
            .delivery-note .product-price,
            .delivery-note .order-items tfoot {
                display: none;
            }
            .delivery-note .head-name,
            .delivery-note .product-name {
                width: 50%;
            }
            .delivery-note .head-quantity,
            .delivery-note .product-quantity {
                width: 50%;
            }
            .delivery-note .order-items tbody tr:last-child {
                border-bottom: 0.24em solid black;
            }
        </style>
    <?php
}
add_action( 'wcdn_head', 'example_price_free_delivery_note', 20 );

Is this the correct way to edit styling for this plugin?

I do not run any caching plugin, nor server based cache, and cloudflare are temporarily disabled.