Make the mobile menu appear at tablet screen size.

Deas 

First of all, thank you very much for your wonderful plugin!

I'm facing an issue where I need the mobile menu to appear at tablet screen size (around 900px). Currently, it only appears at 768px.
I tried modifying the code but wasn’t successful.

Please note that I'm using SmartMenus version 1.1.x.

Can anyone help with this?