Square check boxes and round radio buttons

I like having the check boxes on multi-select questions be square and single-choice radio buttons round. Most of the form themes don't offer this option and in the form designer there isn't a way to mix round and square buttons.

The Big Blue theme does have square checkboxes, but as soon as I go into the Advanced Designer to change the color of the header, they go back to being square.

Is there CSS code I can use to keep those checkboxes square?

Once you change the checkbox / radio button style in the Advanced Designer, also add the next CSS to keep the round radio buttons and square checkboxes.

.form-radio-item,
.form-checkbox-item {
padding-bottom: 6px !important;
}
.form-radio-item:last-child,
.form-checkbox-item:last-child {
padding-bottom: 0;
}
.form-radio-item:not(#foo) label:after,
.form-radio-item:not(#foo) label:before {
border-radius : 50%;
}
.form-checkbox-item:not(#foo) label:after,
.form-checkbox-item:not(#foo) label:before {
border-radius : 0;
}
.form-radio-item:not(#foo) label:before,
.form-checkbox-item:not(#foo) label:before {
border-width : 1px;
}

If you need any further assistance, please let us know.