Load custom CSS for Membership Checkout for specific level - Paid Memberships Pro

load-custom-css-level-pmpro.php

<?php
/**
 * Load custom CSS on checkoutpage for specific membership level in Paid Memberships Pro.
 * Add this code to your PMPro Customizations Plugin - https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
 
 function load_css_for_level_checkout(){

	global $pmpro_pages;
	// Change your membership level ID here.
	if ( is_page( $pmpro_pages['checkout'] ) && isset( $_REQUEST['level'] ) == '1' ) {
		?>
		/* Add Custom CSS below */
		<style type="text/css">
			#other_discount_code_p {display: none;}
			#other_discount_code_tr {display: table-row !important;}
		</style>
		<?php
	}

}
add_action( 'wp_footer', 'load_css_for_level_checkout', 10 );

The comment:
/* Add Custom CSS below */
should be before the ?> tag.