WP Query with custom taxonomy

I’m just getting used to the WP Query and was hoping I could get some assistance on this.

I’ve created a custom taxonomy (theme) and now want to display the latest post with one of these taxonomies on my front page as a top featured post.

Now I can’t really seem to work out how to get it to filter the query properly, maybe someone can correct me:

<?php
           $args = array(
                'tax_query' => array(
                    array(
                        'posts_per_page' => 1,
                        'taxonomy' => 'theme',
                        'field' => 'slug',
                        'terms' => array ('text-image', 'just-text', 'just-image')
                    )
                )
            );
            $query = new WP_Query( $args );
           ?>
           <?php if (have_posts()) : while (have_posts()) : the_post(); ?>

Any help would be highly appreciated, thanks!

EDIT:
Here’s the finished code in case anyone else needs it;

<?php
           $args = array(
            'post_type' => 'post', // it's default, you can skip it
            'posts_per_page' => '1',
            'order_by' => 'date', // it's also default
            'order' => 'DESC', // it's also default
                'tax_query' => array(
                    array(
                        'taxonomy' => 'nameoftaxonomy',
                        'field' => 'slug',
                        'terms' => array ('whatever1', 'whatever2', 'whatever3')
                    )
                )
            );
            $query = new WP_Query( $args );
           ?>
           <?php if (have_posts()) : while( $query->have_posts() ) : $query->the_post(); ?>

Thanks for the help!