NewDay Child Theme Responsive Menu

Hi,

I would like to use the NewDay child theme ( https://www.premiumpress.com/childthemes/?oldtheme=newday/ ) for my responsive directory based website. However, the menu ‘banner’ isn’t responsive. The brown banner design of the menu bar stays a fixed width so if you visit on a mobile device you have to scroll across to the right.

It isn’t just a problem with my site, it doesn’t work on the example theme demo:

https://dp.wlthemes.com/?skin=basic_NewDay

The rest of the content is fine, it’s just the width of the banner causing a problem. Has anybody managed to alter the theme to rectify this issue?