make my checkout col1 and col2 appears side by side
<div class="col2-set" id="customer_details">
<div class="col-1">
<?php do_action( 'woocommerce_checkout_billing' ); ?>
</div>
<div class="col-2">
<?php do_action( 'woocommerce_checkout_shipping' ); ?>
</div>
</div>