div[role=checkbox] {
   margin: 0;
   padding: 0;    
   border: 2px transparent solid;
}

div[role=checkbox]:active {
  background-color: #bbb;
}
  
div[role=checkbox]:hover {
   border-color: #777;
}

div[role=checkbox].focus {
   border-color: black;
}
#example{
   background-color: #F1F1F1 ;
   padding:5px;
}