Issues with CSS Selector

I am facing difficulty with the CSS selector to hide theme menu. I believe I am selecting the wrong CSS selector every time. If I try to hide the theme menu in the header area, the menu in the footer area also disappears in the mobile version. If I choose a selector that makes the footer menu visible, everything from the header disappears except for the responsive menu. I am unable to find the right CSS selector as I am not very good at coding.

The page I need help with: [log in to see the link]