Why does it happen that when you click on the checkbox, you see a box around it?
input[type=checkbox] {
float: left !important;
margin-right: 6px !important;
cursor: pointer !important;
background: #333!important;
border: 1px solid #333!important;
-webkit-appearance: none;
width: 20px;
height: 20px;
border-radius: 50%;
transition: background-color 0.3s, border-color 0.3s;
}
input[type=checkbox]:checked {
background-color: #1565C0!important;
border-color: #1565C0!important;
background-image: url('http://snova.us/data/img/checked.png')!important;
background-size: 10px!important;
background-repeat: no-repeat!important;
background-position: center!important;
}
<input type="checkbox" style="border: 0px;" onchange="setNames(!$(this).is(':checked'));"> Sin nombres</label>