Beautiful schedule grid

Created a new schedule grid that is responsive, and more accurately displays the schedule.  Talk height varies by duration, and the grid falls back to a simple list for mobile (< 768px).

NOTE: The new grid does NOT work on IE 8 or earlier.  The grid also does not work on Android 4.3 or earlier, although mobile devices will not use the grid at all, so that will only affect older Android tablets.  The problem is the use of the calc() function in the CSS.
these should be \DateTime right? because if you plan to use these as Timestamps then it should then be integers
But i think you mean \DateTime or something