RadioButton custom icon

My use case:

I'm using RadioButton.Group for a quiz question. After someone selects an answer, I want to replace the radio part with a green checkmark if they got the answer right, and a red x if they got the answer wrong.

Start by reading the RadioButton.Group and RadioButton component entry points to understand how the radio indicator is rendered and how selection state is passed through. Define the supported custom-icon behavior for selected answers, then verify that the component can show the requested success and failure states without changing existing defaults.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.