On desktop it tries to use Mont-Semibold, which doesn’t seem to be exist:
The line that adds font families:
As you can see it adds Montserrat.
Replies for tickets on suppota
Please change your code to
.evoet_title.evcal_desc2.evcal_event_title{font-size:20px !important;}
Could you tell us elements you want to change font-size of?
Hello,
Have you managed to change it by yourself?
Your code is correct, however just to make sure you can also add !important:
.ajde_evcal_calendar.boxy.boxstyle1 #evcal_list .eventon_list_event .desc_trig { background-color: transparent !important;}
Hello,
Please add this CSS code to EventON > Styles (If you don’t see any change, EventON > Scripts & Styling > turn off Write dynamic styles to header > save settings > turn on Write dynamic styles to header):
.eventon_events_list .eventon_list_event .evoet_cx span.evcal_desc2, .evo_pop_body .evoet_cx span.evcal_desc2 { font-size: 24px; }
.eventon_events_list .eventon_list_event .evoet_cx span.evcal_event_subtitle, .evo_pop_body .evoet_cx span.evcal_event_subtitle { font-size: 16px; }
.eventon_events_list .eventon_list_event .evcal_desc .evcal_desc_info, .eventon_events_list .eventon_list_event .evoet_cx .level_3, .evo_pop_body .evcal_desc .evcal_desc_info, .evo_pop_body .evoet_cx .level_3 { font-size: 12px; }
Follow the css customization guide to further edit style changes.

I want the event top to look like on your demo page.
[add_eventon eventtop_style='2']

Can I also remove the Can not make it to this event?
We won’t need them to keep updating their RSVP’s…
Thanks again,
Dan

Sorry I promise once I’ve worked through the process end-to-end these messages will stop 😉
Can you also remove the YES button?
Is there a [date] and [time] field ? it has an [event-name] field…
Thanks
Dan 🙌