Hi Peter,
Thanks for reaching out to us! Let me say that the calendar on your site looks great to me 🙂
I see the template you use is heavily styling the calendar – that’s why it looks different. The demo site uses just the plugin styles. You can try switching the calendar look settings at WP-Admin > Events > Settings > Display, options Default stylesheet used for events templates and Events template. If this doesn’t work you can try and reach out to the plugin author to ask about this.
Please let me know if you figure it out,
Best,
Nico