Hi,
Well, radio buttons are pretty tough to customize in general, most solutions require adding different kinds of elements here and there. I have found one pure custom CSS solution, like so:
div.asp_w.asp_sb.searchsettings input[type=radio]:not(old) {
display: inline-block;
-webkit-appearance: none;
-moz-appearance: none;
-o-appearance: none;
appearance: none;
border-radius: 1em;
border: 5px solid #555 !important;
}
div.asp_w.asp_sb.searchsettings input[type=radio]:not(old):checked{
border: 5px solid #bb4c4c !important;
}
I don’t think there is any better solution for this at the moment, without major modifications.