I want to do this, because the hugo website is on of a bunch of websites that shall use the same top and footer navigation and the same css and js. The other websites are served by wiki and cms systems.
OK, but as Apache SSI needs … Apache to work, you can add the includes, but they will not show until you push your site to a Apache server. So I would find a way to pull those SSIs in as partials via a script of whatever.