Add the system-ui font family (vercel#1555)

mvasilkov · impronunciable · commit aa4105e00139 · 2017-03-29T11:55:26.000-03:00
diff --git a/lib/error-debug.js b/lib/error-debug.js
@@ -50,7 +50,7 @@ const styles = {
   },
 
   heading: {
-    fontFamily: '-apple-system, BlinkMacSystemFont, Roboto, "Segoe UI", "Fira Sans", Avenir, "Helvetica Neue", "Lucida Grande", sans-serif',
+    fontFamily: '-apple-system, system-ui, BlinkMacSystemFont, Roboto, "Segoe UI", "Fira Sans", Avenir, "Helvetica Neue", "Lucida Grande", sans-serif',
     fontSize: '15px',
     fontWeight: 'bold',
     color: '#febfdd',
