Sometimes, the comment form don't appear and all "Reply" button within each comment are inactive. After forcing the refresh (CTRL + F5), everything is OK.
Put the code in the "Custom CSS code" textarea, located in the Dashboard > wpDiscuz > Settings > Styles & Colors admin page.
Don't forget to delete the caches before checking.
In case you want to say thank you! 🙂 We'd really appreciate if you leave a good review on the plugin page. This is the best way to say thank you to this project and the support team.