Change layout from four columns to three columns

Hello there,

I am trying to make the team photos on this page three columns. They are currently four columns and the PHP code is as follows:

<?php
/*
Template Name: Team Template
Template Post Type: post
*/
get_header(); ?>
<section>
	<article>
		<div class="team-detail-main">
			<div class="grid-container">
				<div class="grid-x grid-padding-x" data-equalizer>
					<div class="large-12 cell">
						<div class="tdm-title">
							<h1><?php the_title(); ?><?php $teamposition = get_field('team_position'); ?><?php if( !empty($teamposition) ): ?> - <?php echo $teamposition; ?><?php endif ?></h1>
						</div>
					</div>
					<?php $teamFeatImg = wp_get_attachment_image_src( get_post_thumbnail_id($post->ID), 'full' );?>
					<?php if( !empty($teamFeatImg) ): ?>
						<div class="large-4 medium-4 small-12 cell">
							<div class="tdm-teamfi" style="background-image: url('<?php echo $teamFeatImg[0]; ?>');" data-equalizer-watch></div>
						</div>
					<?php endif; ?>
					<div class="large-8 medium-8 small-12 cell">
						<div class="tdm-content" data-equalizer-watch><?php get_template_part('inc/bodycontainer'); ?></div>
					</div>
				</div>
			</div>
		</div>
	</article>
</section>
<section>
	<div class="grid-x" data-equalizer>
		<?php get_template_part('inc/testimonialbox'); ?>
		<?php get_template_part('inc/cta'); ?>
	</div>
</section>
<?php get_template_part('inc/accreditationlogo'); ?>
<!-- Footer Start -->
<?php get_footer(); ?>
<!-- Footer End -->

I need to work out how to make the layout three columns (there will be soon be two more team members). I am not sure how to do this in PHP, or if I need to look into the CSS file.

Thanks in advance for your help!

Cheers ??

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