Default theme: Fix rem unit

themes/default/style.css

@@ -167,9 +167,11 @@ footer .social {
 
 /*** TEXT ***/
 
+html { font-size: 16px; }
+
 body {
     font-family: 'Droid Sans', 'Helvetica', 'Arial', sans-serif;
-    font-size: 16px;
+    font-size: 1rem;
     line-height: 1.6;
     font-variant-ligatures: common-ligatures;
     text-rendering: optimizeLegibility;