text: addFont.addEventListener("click", e => {
    var fonts = model.fonts.slice(0);
    var currentStylesheet = app.core.currentStyleSheet;
    var ffr = fontFaceRule(fontModel);
    if (!currentStylesheet) {
      app.core.createCurrentStyleSheet(ffr);
    } else {
      app.core.insertCssRule(currentStylesheet, ffr);
      var index = currentStylesheet.cssRules.length;
      var rule = currentStylesheet.cssRules[index - 1];
      var mapped = {
        fontFamily: "",
        fontWeight: "",
        fontStyle: "",
        fontDisplay: "",
        unicodeRange: "",
        fontStretch: "",
        fontVariant: "",
        fontFeatureSettings: "",
        fontVariationSettings: "",
        src: ""
      };
      app.core.styles.fonts.push({mapped, fontFaceRule: rule, cssText: rule.cssText});
      assignModel({detail: app.core});
    }
  });