Horizontal Dropdown menu hides behind header

I have had to do a media query to drop the Header wrapper / Site Title (For the selector - .content-align-right .custom-header-content-wrapper) to have a margin-top: 180px; because the last item in the drop down hides behind the header title text instead of showing over top. The Submenu css I think would be .absolute-header .main-navigation ul.sub-menu a I can only reproduce this on the brave browser or Safari so far, because responsive design mode in say Firefox doesn't show me the error.  It occurs for some of my viewers at  <span id="resolution">1440 x 900 resolution. </span> My media query has fixed it for now, but if we continue to add submenu items then the last ones will be hiding again, and I can't drop the header wrapper any more. Is there a fix to make the dropdown show overtop of the header wrapper?