@* Lightning Now! *   In the Lightning Now tour - there was a brief presentation on the code necessary to update a VF component to use the Lightning Design System.   It was also mentioned however, that you don't want the LDS to affect the way the VF pages look in classic — and so it was suggested that you built conditional logic to use LDS IF the user was logged into lightning, but not to do so if the user was logged in classic.

Can someone point me to the resource and/or slides or code that would show the apex code to create that conditional logic?