adding html font size value back in again

Author: chrisdavidmills

learn/values-units/em-rem.html

@@ -11,6 +11,10 @@
     </style>
 
     <style class="editable">
+      html {
+        font-size: 16px;
+      }
+
       .ems li {
         font-size: 1.3em;
       }
@@ -59,6 +63,10 @@
     </section>
 
     <textarea class="playable playable-css" style="height: 280px;">
+html {
+  font-size: 16px;
+}
+
 .ems li {
   font-size: 1.3em;
 }