Hi,

That's 100% responsive. And you've make it doesn't responsive by set a background image for your topbar.

I recommend you remove the background on topbar for small screen by add more this code to Customize > Custom CSS:

\
@media only screen and (max-width: 1000px){\
.topbar-menu{ background-image: none; }\
}

Best Regards,

PenciDesign