Hi,

Read & Try >> https://www.joomshaper.com/documentation/helix-framework/troubleshooting-faq#off-canvas-menu-doesnt-appear

In your case you need Custom CSS to change color of [=] lines from white to black to see them

#sp-menu1 .icon-bar > span {border-bottom: 1px solid #111;}

Bonus tip

And please for Mobile logo use different image file without top and bottom empty spaces, cropped. And then it will look much better on all smartphones.