Gantt in Excel spanning over 3 days with hours

Hello Friends - I am trying to make a Gantt in excel for a project that will span over 3 days with activities happening during 24 hours on each of the 3 days.
I am trying to make a Gantt by entering Day and Time for each activity's start and end time, but the conditional formatting formula that I am using is not working out to make the Gantt move across Days. You can figure this out in the attached sample.

Please could one of the experts help me in overcoming this hurdle.

Thanks
Jugal