@jan10 It appears there's something wrong with my specific computer and its status on the network. Precisely the same browser configuration (Chrome updated) on another Mac Air is working exactly to spec, and the theme displays fine on that second computer. So I believe there's something wrong with the first Mac Air that prompted my initial post. I hate it when threads go dry so when I know for sure I'll post an update here. Thanks!
(I purchased two licenses of the Big Bang premium WordPress theme.)