How to make media qwery mobile only?

Question

Adaptive design

I do this: But the customer has a width of 1080px on mobile. How to define media qwery for mobile only? The question arose due to the fact that I changed the code in , but he does not see the changes on his phone. Or is it still not because of the expansion?
@media (max-width: 920px)
@media (max-width: 920px)