problem with changing the width

I have a problem with the comments by Disqus. I would like to change its width. I found a similar topic on the forum, where the solution was to modify the css file and more specifically line

# disqus_thread {width: 300px! Important;}.

And here there was a problem. Nowhere can I find this line. Not in the skin css file that I use. The plugin works correctly. Can someone please advise how to get out of this situation?

Thanks for help !

https://www.rysiekriedel.pl/rysiek-riedel/

https://www.ads-software.com/extend/plugins/disqus-comment-system/