Hey there!
The good news is that the Old Post Date Remover css file is being loaded on that page (line 2299 of the source), so now we just have to get your theme to wrap the date in a span or div that makes it hide-able.
Your theme is currently not putting any div or span around the date, simply wrapping it in an H6 heading.
What that means is that I can’t issue a patch to hide the date on your site without it hiding any h6 headings on one of the other 5,000+ active sites where my plugin lives.
In order to hide the date, I’d recommend wrapping the date in a div with a class of “date.” In most themes, that would happen in the content.php file.
Let me know is you need extra help with that. For starters, never update php files through the dashboard editor, always use FTP, SSH, or some other method to transfer the edited files to your server. (I recommend using a staging site.)
Thanks for using my plugin!