Make custom max-width on row conform to Boostrap convention

Bootstrap break point for tablet portrait 768 keeps the row intact, so it's not appropriate to have off-canvas elements at that width. Custom off-canvas.css should be breakpoint 767px

examples/offcanvas/offcanvas.css

@@ -14,7 +14,7 @@ footer {
  * Off Canvas
  * --------------------------------------------------
  */
-@media screen and (max-width: 768px) {
+@media screen and (max-width: 767px) {
   .row-offcanvas {
     position: relative;
     -webkit-transition: all 0.25s ease-out;