okay.. in my case I have this radio-button group:
<div class="form-group input-radio">
<label for="field_14" class="control-label label-14 label-hidden">
kommt *
</label>
<div class="form-control-div">
<div class="btn-group" data-toggle="buttons">
<label class="btn btn-default">
<input type="radio" name="field[14]" id="field_14_0" class="form-control required" value="yes" required="required" />
Juhu!
</label>
<label class="btn btn-default">
<input type="radio" name="field[14]" id="field_14_1" class="form-control required" value="no" required="required" />
Nein...
</label>
</div>
</div>
</div>
So I tried to modify the Custom Styles in my customizer like this:
.form-control {
background-color: #300;
}
.form-control:focus {
background-color: #000;
}
.form-control:checked {
background-color: #f00;
}
but nothing worked!?