@media (min-width: 769px)
nav .main-nav .mega-menu > ul > li:hover > a, nav .main-nav .mega-menu > ul > li:focus > a, nav .main-nav .mega-menu > ul > li[class*="current-"] > a, nav .main-nav .mega-menu ul ul {
background-color: transparent !important;
color: inherit;
}
Remove that and it should inherit the settings in the customizer.