If you need to target specific elements with css based on membership level in paid memberships pro here's a snippet.

pmp_pro_echo_body_class.php

<?php
/* Dont Include This Comment or the opening <?php tag */

/*************************************
*
*  Add a body class correlating to the users 
*  memberhsip level in Paid Memberships Pro
*  looks like - 'member-level-1'
*
**************************************/
add_filter( 'body_class', 'add_paid_member_body_class' );
 function add_paid_member_body_class($classes) {
     if ( is_user_logged_in() && function_exists('pmpro_hasMembershipLevel') && pmpro_hasMembershipLevel() ) {
         global $current_user;
         $current_user->membership_level = pmpro_getMembershipLevelForUser($current_user->ID);
         $classes[] = 'member-level-' . $current_user->membership_level->id;
     }
     return $classes;
 }