Because you forgot to put back the px from the css code fontsize, this is why it doesn't make any different on the site.
Actually i am not encourage user to modify the core code in Easyblog, because once you put these modification file into your current template, it will always referring to these template override file, so if we have fix something in this file in the future, then you have to double check this template file and make sure manually update to latest code.
By the way, i already updated the code changed h1 to h2 under this template override file location JoomlaFolder/templates/cbn_reimagined_text_standard/html/com_easyblog/blogs/entry/default.posts.php
, can you check again is it look fine now?