Sharing: Style page_category_index.php for Sample Theme http://oncecoupled.com/2014/06/page-template-list-posts-by-category/#comment-6043

page_category_index.php

<?php
/**
* Template Name: Category Index
* Created By: Lauren Gray Designs
* URL: http://oncecoupled.com
*/
 
// Remove the loop and replace it with our own
remove_action( 'genesis_loop', 'genesis_do_loop' );
add_action( 'genesis_loop', 'LGD_add_archive', 9 );
 
function LGD_add_archive() {
 
	$args = array(
		'type' => 'post',
		'orderby' => 'name'
	);
	
	$categories = get_categories( $args );
	
	echo '<div class="entry">';
	
	// List each category
	foreach($categories as $category) {
	
		// Output the cateogry (and link to it)
		echo '<ul><li><h3><a href="' . get_category_link( $category->term_id ) . '" title="' . sprintf( __( "View all posts in %s" ), $category->name ) . '" ' . '>' . $category->name . '</a></h3><ul>';
		
		$args = array( 
			'posts_per_page' => -1,
			'category' => $category->term_id
		);
			
		$myposts = get_posts( $args );
		
		// List the posts in said category
		foreach ( $myposts as $post ) : setup_postdata( $post );
		
		echo '<li><a href="' . get_permalink( $post->ID ) . '">' . get_the_title( $post->ID ) . '</a></li>';
		
		endforeach;
		
		// Close everything up
		echo '</li></ul></ul><br><br>';
		
	}
	
	echo '</div>';
	
}
 
genesis();

style.css

.page-template-page_category_index-php .content {
  background-color: #fff;
  margin-bottom: 40px;
  padding: 50px 60px;
}