I’m having a lot of trouble finding the solution.
I would like to loop my last 3 posts with wp-query.
I would like the 1st post to be in one div and the last 2 posts in another different div.
So when I publish a new post the last post goes to div 1 and the previous one goes down to the 2nd div etc…

here is an example

$args = array(
    'post_type' => 'post',
    'post_per_page' => 3,
);

<?php $loop = new WP_Query($args);

$count = 0;
 while ($loop->have_posts()) : $loop->the_post();
if ($count == 0):
?>

    <!-- last post -->
    <div class="post-one">
        <h1><?php the_title();?></h1>
    </div>
<?php else:?>

    <!-- second et third post -->
    <div class="post-two">
    <h2><?php the_title();?></h2>
        <?php the_excerpt();?>
    </div>

<?php
$count ++;
endif;
endwhile;
wp_reset_postdata();?>