my comment only referred to applying the right formatting for a specific page;
you still need to remove the sidebar for that page, possibly by creating a page template https://codex.www.ads-software.com/Pages#Page_Templates (just a copy of page.php with the necessary extra coding at the top, where you remove the <?php get_sidebar(); ?> line.
plus more formatting with possible changes to other styles to stretch the content (which will then scroll through the site title and tag line …)
‘the devil is in the detail’
a bunch of extra useful css:
.page-id-1446 #sidebar-primary .sidebar { display: none; }
.page-id-1446 #sidebar-primary { background: #fff; padding-top:20px;margin-top:-20px; }
.page-id-1446 #main { width:100%; }
.page-id-1446 #content { width:95%; }
.page-id-1446 #page { width:94%; }
the first line of those does virtually the same job as creating a page template – it hides the sidebar.