Display table and cells borders in preview/default template

[WHISK4S]

Preview in browser doesn't show Table outlines.
To re-enact the issue.
Using the menu item; View -> View Document in Browser
also the same output is seen with File -> Export as HTML -> Default template.
Exporting with Github template is showing the tables correctly though. I think it might be the template used.

--- exact line used below ---

TABLE

item	desc
ab	123
cd	456

abricotine_1.1.4_amd64.deb (dark theme, thank you!!)
elementary OS 5.1.7 Hera, Gnome (Gtk 3.22.30-1ubuntu4), 5.0.0-37-generic x86_64

[brrd]

Yes, this comes from the template stylesheet.

We can add it.