Styling the WooCommerce "Quantity Buttons"

Hy,

I’m making my own the for the Woocommerce plugin with the Zurb Foundation Framework CSS.

I am looking for a way to styling the “quantity buttons”.
The woocommerce plugin generate this code HTML :

<div class="quantity buttons_added">
<input class="minus" type="button" value="-">
<input class="input-text qty text" type="number" size="4" title="Qté" value="1" name="quantity" min="1" step="1">
<input class="plus" type="button" value="+">
</div>

But I want to override it with my own HTML code.

The only code I found it is this one:

<?php do_action( 'woocommerce_before_add_to_cart_button' ); ?>

			 	<?php
			 		if ( ! $product->is_sold_individually() )
			 			woocommerce_quantity_input( array(
			 				'min_value' => apply_filters( 'woocommerce_quantity_input_min', 1, $product ),
			 				'max_value' => apply_filters( 'woocommerce_quantity_input_max', $product->backorders_allowed() ? '' : $product->get_stock_quantity(), $product )
			 			) );
			 	?>

But there are no HTML in there. Only PHP.
Where can I find the HTML code to put my own CSS class?

Thanks for your help.

Kevin