input[type=radio] {
  border: 1px solid #fff;
  padding: 0.5em;
  -webkit-appearance: none;
}

input[type=radio]:checked {
  background: url(data:image/gif;base64,R0lGODlhAQABAPAAAP///////yH5BAAAAAAALAAAAAABAAEAAAICRAEAOw==) no-repeat center center;
  background-size: 9px 9px;
}

input[type=radio]:focus {
  outline-color: transparent;
}