.sydney-offcanvas-menu CSS has colour values missing

Whilst poking around in in the browser console to finesse some CSS (close button all but invisible on mobile menu) I observed CSS errors in respect of the .sydney-offcanvas-menu CSS class selector.

color and background-color do not have values assigned to them.

Such might account for the black background of the mobile menu and the consequential near invisibility of the close button. Note the linked to page has a CSS modification to make the background of the close button white and circular.

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