I would like to create an HTML form for user feedback.
If the overall feedback is good, the user should click on a laughing smiley, if the overall feedback is bad, the user
You cannot style things like radio buttons, checkboxes, scrollsbars (etc.) at all. These are native to the OS and the browser and not something you can manipulate.
You can simulate this, however by hiding the radio buttons and only showing an image instead as in.