HOW TO add a drop SHADOW (or box shadow) on the Event thumbnails on the Events page?

HOW TO add a drop SHADOW (or box shadow) on the Event thumbnails on my events-page?

Is it something like this?:

.list-item{
  border-radius:10px!important;
  box-shadow: 5px 5px 10px #000!important;
  border:6px solid #fff!important;
}

Cant figure out the ID for the Event Thumb nails on the event page... Thanks for any help - I appreciate it!

Oh wait - just found this: 

Thanks again TUANPHAN!

All Best !

a.eventlist-column-thumbnail.content-fill{
  filter: drop-shadow(4px 4px 8px #000000) !important;
}