Comments tag h2 navigation tag h3

good morning
I remove post navigation and comments. with this css

.entry-footer,.single .post-navigation {  
   display: none;
}
#comments {  
   display: none! important;
}

but the h3 tag remains: leave a comment cancel reply.
and h2 : post navigation.
i need to remove (is no good for seo)
can you help me eliminate it? in sydney I modified the single.php file.
but Astrid is difficult for me. is hard to undestand
the site is www.restaurolandiacg.it
one example article page:
.www.restaurolandiacg.it/rigenerare-divani-a-torino/
in italian tag h2 is Navigazione articoli
e h3 is lascia un commento ed annulla risposta
sorry for my english

tnks

Hello there,

Please take a screenshot and put some annotations to indicate where h2 and h3 tags can be found at; and upload it in your next reply. Honestly I couldn’t get where they are. Sorry.

Regards,
Kharis

Honestly they are in thema engine (post page) (comment engine)
annotation is :
post : www.restaurolandiacg.it/rigenerare-divani-a-torino/ or all post page : https://www.restaurolandiacg.it/post-sitemap.xml
h2 is Navigazione articoli
h3 is lascia un commento ed annulla risposta
screenshot is any tool for example :https://suite.seotesteronline.com/
is urgent tnks

please i need a reaply

hi
i change a thema
tnks