S:\beseit\wp-content\themes\twentyeleven/page-maxima-amplada.php

<?php
/*
Template Name: maxima amplada
Description: Plantilla de pàgina sense barres laterals, màxima amplada possible.
*/

add_action('wp', function() {
    if ( did_action('template_redirect') ) return;
    // Exemples (descomenta/adapta segons tema):
    // remove_action('storefront_sidebar', 'storefront_get_sidebar', 10);
});

get_header(); ?>

<style type="text/css">
.page-maxima-amplada-fullwidth,
.page-maxima-amplada-fullwidth .content,
.page-maxima-amplada-fullwidth .site-content {
    width: 100% !important;
    max-width: none !important;
    padding-left: 0 !important;
    padding-right: 0 !important;
    margin-left: 0 !important;
    margin-right: 0 !important;
}

.sidebar, .widget-area, .site-sidebar, #secondary {
    display: none !important;
}

.page-maxima-amplada-inner {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

.page-maxima-amplada-inner .entry-title {
    margin: 20px 0 10px 20px;
    text-align: left;
}

.page-maxima-amplada-inner .entry-meta {
    margin: 0 0 30px 20px;
    font-size: 0.9rem;
    color: #666;
    font-style: italic;
}
</style>

<div id="primary" class="content-area page-maxima-amplada-fullwidth">
    <main id="main" class="site-main page-maxima-amplada-inner" role="main">

    <?php
    while ( have_posts() ) : the_post();
        echo '<h1 class="entry-title">' . get_the_title() . '</h1>';
        echo '<div class="entry-meta">Publicat el ' . get_the_date('j F Y') . '</div>';

        echo '<div class="entry-content">';
            the_content();
        echo '</div>';

    endwhile;
    ?>

    </main><!-- #main -->
</div><!-- #primary -->

<?php get_footer();
?>