Update responsiveness.html

docs/documentation/overview/responsiveness.html

@@ -208,7 +208,7 @@ $fullhd-enabled: false
       </tbody>
     </table>
     
-    {% assign vernum = site.version | replace: "." "" | plus: 1 | minus: 1 %}
+    {% assign vernum = site.version | downcase | remove: "." | plus: 0 %}
 
     {% if vernum >= 63 %}