.checkboxGroup
{
/*         white-space: pre; */
    display: inline-block;
}

#form span::after
{
    content: "|| ";
}
#form span:last-of-type::after
{
    content: "";
}

label {
    white-space: nowrap;
}

label input {
    visibility: hidden;/* <-- hide the default checkbox, the rest is to hide and alllow tabbing, which display:none prevents */
    display: block;
    height: 0;
    width: 0;
    position: absolute;
    overflow: hidden;
}

label span {/* <-- style the artificial checkbox */
    height: 10px;
    width: 10px;
    border: 1px solid grey;
    display: inline-block;
    margin-right: 5px;
}