Photogra Theme Default Page Template Width

I’m looking to make the DEFAULT Template full width rather than the narrow column that it does. You can see what I need here: https://wp.me/P5LS60-Ta

Looked through my CSS files but I’m not much good on this I’m afraid!

Here’s my PAGE TEMPLATE – PAGE.PHP

<?php get_header(); ?>

<?php while ( have_posts() ) : the_post(); ?>

<?php if (has_post_thumbnail()): ?>
<div id="about-background">
<?php $image = wp_get_attachment_image_src(get_post_thumbnail_id(get_the_ID()), 'full'); ?>
<?php if ($image && isset($image[0])): ?>
<?php printf('<img src="%s" alt="%s" />', $image[0], get_the_title()); ?>
<?php endif; ?>
</div>
<?php endif; ?>

<section id="column-content">
<h1 class="page-title"><?php the_title(); ?></h1>
<div class="the-content">
<?php the_content(); ?>
</div>
</section>

<?php endwhile; ?>

<?php get_footer(); ?>