How does bootstrap work on full hd(1920×1080) mobiles?

The Bootstrap tutorial says that include .col-xs-* for mobile devices(<768px). My question is that, if I make a website for small mobiles using .col-xs-* classes then that css rule will be applied only to those devices which have width less than 768px. Nowadays there are full hd mobiles which have width 1080px in 5 inch display. So would these mobile behave as Desktop computer(≥992px) for my bootstrap css? I want my css to be same for any 5 inches screen mobile device, be it HD or Full HD.