Follow up from
The body's classes do not follow Drupal 8's CSS coding standards, we have classes that have never been used:
.html, strange empty classes (page-node-), etc.
html front / not-front not-logged-in / logged-in in-maintenance page-node page-node- page-node-$nid ...
Drupal will provide the following classes as default in
.path-frontpage (if on the frontpage) .path-$path (first part of the path - .path-admin, .path-node) .user-logged-in .page-maintenance (existing class to use instead of in-maintenance)
User interface changes
Markup/CSS class changes only.