WordPress Hide admin elements

functions.php

function prefix_admin_hide_contents() {
 $admin_user = wp_get_current_user();
 if( $admin_user->ID != '5' ) {
  echo '<style>';
   echo '.element { display: none; }';
  echo '</style>';
 }
}
add_filter( 'admin_head', 'prefix_admin_hide_contents' );