Structure of the radio and how its internal parts are composed. These are the radio's semantic parts, so they are also what the classNames and styles objects accept. A button-style option from optionType="button" has the same three parts.
Name
Description
1
root
The <label> around the circle and the text, so a click anywhere on it selects the option. className lands here.
2
icon
The circle, holding the real <input type="radio">. It draws the inner dot when the option is checked.
3
label
The text you pass as children, with the gap to the circle. It only renders when there are children.