Ad banner below menu won't stay centered / maintain width when resized

So,

I use adrotate and an also using a header style that doesn’t have a banner ad by default. I added some simple PHP ad roate code to the header. See below/
<div class=”td-header-menu-wrap td-header-gradient <?php echo $menuSearchClass ?>”>
<div class=”td-container td-header-row td-header-main-menu”>
<?php locate_template(‘parts/header/header-menu.php’, true);?>

</div>
<?php echo adrotate_group(5); ?>
</div>
</div>
I am trying to style this using .g.g-5 I cannot make this add stay centered and full width when sizing down. Any help would be greatly appreciated.

TG