text: import {MDCRipple} from '@material/ripple/index';
  import {MDCTextField} from '@material/textfield/component';
  
  const ripple = new MDCRipple(document.querySelector('.signin-button'));
  const usernameTF = new MDCTextField(document.querySelector('.username-textfield'));
  const passwordTF = new MDCTextField(document.querySelector('.password-textfield'));
  