Adds a custom class for the first post, on the first page of index and archive pages.

Highlight First Post.php

<?php
	if( $wp_query->current_post == 0 && !is_paged() ) {
		post_class('first-post');
	} else {
		post_class();
	}
?>




<? // The same code in a single line ?>

<?php if( $wp_query->current_post == 0 && !is_paged() ) { post_class('first-post'); } else { post_class(); } ?>



LOOP COUNTER
<section id="the-big-stories">
<?php $the_big_stories = new WP_Query('tag=highlights&showposts=3'); ?>
<?php if ( $the_big_stories->have_posts() ) : ?>
	<?php while ($the_big_stories->have_posts()) : $the_big_stories->the_post(); $the_big_story_counter++; ?>
		<article id="big-story-<?php echo $the_big_story_counter; ?>">
			<?php //the_post_thumbnail( 'the_big_stories_thumb' ); ?>
			<div><img src="http://placehold.it/440x248"></div>
			<h1 class="entry-title"><a href="<?php the_permalink(); ?>" title="<?php echo esc_attr( sprintf( __( 'Permalink to %s', 'doraemon' ), the_title_attribute( 'echo=0' ) ) ); ?>" rel="bookmark"><?php the_title(); ?></a></h1>
		</article>
	<?php endwhile; ?>
<?php else : ?>
	<?php get_template_part( 'no-results', 'index' ); ?>
<?php endif; ?>
</section><!-- #content .site-content -->