WordPress | Get Posts with adaptive column widths

get_posts_adaptive_columns.php

<style>
ul {margin:0; padding:0; list-style:none; overflow:auto}
ul li {float:left}
ul.half li {width:50%}
ul.thirds li {width:33.33%; width:calc(100% / 3)}
ul.quarters li {width:25%}
</style>
<?php
$args = array(
	'posts_per_page' => 100,
	'post_type' => 'posts'
);
$posts = get_posts( $args );
if ( $posts ) {
	$count = count( $posts );
	echo '<ul class="';
	if ( $count <= 2 || $count == 4 ) {
		echo 'half';
	} elseif ( $count == 3 || $count == 5 || $count == 6 || $count == 9 ) {
		echo 'thirds';
	} else {
		echo 'quarters';
	}
	echo '">';
	foreach ( $posts as $post ) : setup_postdata( $post ); 
		$title = get_the_title();
		$url = get_the_permalink();
		echo '<li>';
		echo '<h3>';
		echo '<a href="' . $url . '">' . $title . '</a>';
		echo '</h3>';
		echo '</li>';
	endforeach; 
	echo '</ul>';
}
wp_reset_postdata();
?>

Get those posts but leave out the empty space guvner

Essentially this is a responsive/adaptive get_posts list, which adjusts the widths of the list items based on how many list items there are. It first uses count to return the number of posts and then applies a class to the UL which ensures there's no empty space on each row or, at least, minimal space.