Sidebar menu toggle not working

I’m working on a site for a client using the Drento free theme. The menu hamburger toggle button isn’t working, and apparently hasn’t since he started using the theme.

We’re not using the floating social button or the floating search button, but I tested them and found that they’re not working either.

I presume it’s a problem with Javascript, but I haven’t been able to isolate it. I tried disabling plugins, but it didn’t help.

Has anyone else experienced this problem?

https://arman.jaanfx.com