@mgmeyers and @manuelalonso
I encounter this same issue today.
I had to add height and width to my checkbox styling in my snippets file to get them to show up. I hope this helps.:
input.task-list-item-checkbox {
appearance: none;
-webkit-appearance: none;
border-radius: 50%;
border: 1px solid red;
width: 18px; <---
height: 18px; <---
}
When I did, my custom checkbox style showed up in my kanban instead of a small dot.
Before:
After I added the height and width:
