You broke when you added this HTML in your theme inside the head tag:
<center>
<img src="http://elenaspivakova.com/wp-content/uploads/2024/02/dialog_red_woman.png" alt="centered image" height="52" width="200" padding="" -="" top:="" 40px;;="">
</center>
Be careful when editing your theme, because you can break Discourse with invalid markup.
You need to move this to the body sections.