Hi, You shouldn’t have replaced the customized CSS with the default one.
This code added to sweetdate-child/functions.php will make the bbPress pages full width: 
COPY CODE
add_action('wp_head', 'kleo_bbpress_tpl', 11);
function kleo_bbpress_tpl() 
{
	//user is viewing a forum page
	if(get_post_type() == 'forum' OR get_post_type() == 'topic' OR get_post_type() == 'reply') {
	//set to full width
	remove_action('kleo_before_content', 'kleo_sidebar');
	remove_action('kleo_after_content', 'kleo_sidebar');
	remove_action('kleo_before_content', 'kleo_extra_sidebar');
	remove_action('kleo_after_content', 'kleo_extra_sidebar');
	add_filter('kleo_content_class', create_function(null, 'return "twelve";'));
		
	}
}
 
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