I found the problem. The css rule that sets the padding for the div.tribe-events-pg-template also uses a dynamically created class of a parent div. When the 2014 theme is used, the parent div’s class name is .tribe-theme-twentyfourteen. That div has a different class name in my child theme. I added a rule to my parent theme to use the new class name and set the padding appropriately. All is well!