Hi olaf@xso,
Add the following CSS to you CSS stylesheet and import it in your App.vue file:

@font-face {
  font-family: 'Material Icons';
  font-style: normal;
  font-weight: 400;
  src: url(https://example.com/MaterialIcons-Regular.eot); /* For IE6-8 */
  src: local('Material Icons'),
    url(https://example.com/MaterialIcons-Regular.woff2) format('woff2'),
    url(https://example.com/MaterialIcons-Regular.woff) format('woff'),
    url(https://example.com/MaterialIcons-Regular.ttf) format('truetype');
.material-icons {
  font-family: 'Material Icons';
  font-weight: normal;
  font-style: normal;
  font-size: 24px;  /* Preferred icon size */
  display: inline-block;
  line-height: 1;
  text-transform: none;
  letter-spacing: normal;
  word-wrap: normal;
  white-space: nowrap;
  direction: ltr;
  /* Support for all WebKit browsers. */
  -webkit-font-smoothing: antialiased;
  /* Support for Safari and Chrome. */
  text-rendering: optimizeLegibility;
  /* Support for Firefox. */
  -moz-osx-font-smoothing: grayscale;
  /* Support for IE. */
  font-feature-settings: 'liga';

If you don’t want to fetch the icons from the web and instead use yout localy downloaded files from NPM just replace the urls in the font-face with the path to the appropriate files in your local storage.
Best Regards,
Smart HTML Elements Team