Update style.css

Responsive design is currently broken when the width is between 768px and 850px, because the width of inner class is set fixed at 850px

themes/default/style.css

@@ -214,7 +214,8 @@ dd {
 /* Structure Styles
 /*---------------------------------------------*/
 .inner {
-    width: 850px;
+    width: 100%;
+    max-width: 850px;
     margin: 0 auto;
 }