.group div[role=checkbox] {
   margin: 0;
   padding: 0;    
   border: 2px transparent solid;
   margin-bottom: .5em;
   margin-top: .5em;
}
.group label{
   display: block;
   border: thin transparent solid;
   margin-left: 18px;
}  
.group div[role=checkbox]:hover,
label:hover {
   border-color: #777;
}

.group div[role=checkbox].focus,
label.focus {
   border-color: black;
}
.checkbox{
   padding-left: 10px;
}
#ex1, #ex2, #ex3 {
   background-color: #F1F1F1 ;
   padding:10px;
}
fieldset {
   border-style: none;
}