Mobile menu issue

I have an issue with my header menu when I open it on a mobile device, instead of opening on the center of the screen under the hamburger icon it opens outside of the screen on the right.

I use WordPress for this site, I contacted the developers’ support forum, and it appears it works fine for them, but for the time being it is not fixed.

Check this link for how the menu appears when on mobile.

Is there a way to fix it with CSS?