Print page content BEFORE more tag, with formatting

I have this code working to get the content of the page in question (id 26):
<?php $id=26; $post = get_page($id); echo $post->post_content; ?>

What do I add to that code – or what other code can I use to
1. get the content BEFORE the more tag of a specific page
2. keep the formatting of the content?

thanks,
page in question is https://sublime-dezine.com