Rolling forward https://codereview.chromium.org/1155683008/ which was

third_party/polymer/v0_8/components/paper-radio-button/paper-radio-button.css

-/*
-Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
-This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
-The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
-The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
-Code distributed by Google as part of the polymer project is also
-subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
-*/
-
-:host {
-  display: inline-block;
-  white-space: nowrap;
-}
-
-:host(:focus) {
-  outline: none;
-}
-
-#radioContainer {
-  display: inline-block;
-  position: relative;
-  width: 16px;
-  height: 16px;
-  cursor: pointer;
-  vertical-align: middle;
-}
-
-:host #ink {
-  position: absolute;
-  top: -16px;
-  left: -16px;
-  width: 48px;
-  height: 48px;
-  color: var(--paper-radio-button-unchecked-ink-color);
-  opacity: 0.6;
-}
-
-:host #ink[checked] {
-  color: var(--paper-radio-button-checked-ink-color);
-}
-
-:host #offRadio {
-  position: absolute;
-  top: 0px;
-  left: 0px;
-  width: 12px;
-  height: 12px;
-  border-radius: 50%;
-  border: solid 2px;
-  border-color: var(--paper-radio-button-unchecked-color);
-  transition: border-color 0.28s;
-}
-
-:host #onRadio {
-  position: absolute;
-  top: 4px;
-  left: 4px;
-  width: 8px;
-  height: 8px;
-  border-radius: 50%;
-  background-color: var(--paper-radio-button-checked-color);
-  -webkit-transform: scale(0);
-  transform: scale(0);
-  transition: -webkit-transform ease 0.28s;
-  transition: transform ease 0.28s;
-}
-
-:host([checked]) #offRadio {
-  border-color: var(--paper-radio-button-checked-color);
-}
-
-:host([checked]) #onRadio {
-  -webkit-transform: scale(1);
-  transform: scale(1);
-}
-
-#radioLabel {
-  position: relative;
-  display: inline-block;
-  vertical-align: middle;
-  margin-left: 10px;
-  white-space: normal;
-  pointer-events: none;
-  color: var(--paper-radio-button-label-color);
-}
-
-#radioLabel[hidden] {
-  display: none;
-}
-
-/* disabled state */
-:host([disabled]) {
-  pointer-events: none;
-}
-
-:host([disabled]) #offRadio {
-  border-color: var(--paper-radio-button-unchecked-color);
-  opacity: 0.5;
-}
-
-:host([disabled][checked]) #onRadio {
-  background-color: var(--paper-radio-button-unchecked-color);
-  opacity: 0.5;
-}
-
-:host([disabled]) #radioLabel {
-  /* slightly darker than the button, so that it's readable */
-  opacity: 0.65;
-}