Airi Menu Spacing on PC vs Mac

I am using the Airi theme for my website. The menu formatting on PC and Mac looks different.
On the PC the menu runs into 2 lines, however on the Mac laptop it looks fine. How do I make the format consistent (i.e. the menu should fit into 1 line only). I have included a screenshot from my PC for your reference. My website:

Airi theme Menu on PC

Thank you very much.