/layouts/partials are customizations used to tweak overall CSS paramaters of the site. Generally these are reserved for use by ALL repos and can be changed by emailing Fortinet Cloud CSE team
If you absolutely must change something, use Hugo Partials as your guide
Partials are automatically included in the site’s CSS configuration
Shortcodes - custom HTML
If you need to use complex and/or custom HTML in your guide, use a custom shortcode.